JPH0370909B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a bidirectional optical switch that turns on and off direct current or alternating current using light, and is particularly applicable to a bidirectional switch in a telephone line network. .

[Conventional technology] Conventional semiconductor bidirectional switches include triacs, gated diode switches, and gated diode switches.
There is a Diode Switch (hereinafter abbreviated as GDS).
Triacs are semiconductor devices that control alternating current signals, and it is well known that they are widely used.
An example of GDS is the structure shown in Figure 14.
It has the ability not only to control AC signals but also to interrupt DC signals, making it resistant to large current surges. In FIG. 14, 1 is a polysilicon base, 2 is an insulating layer,
3 is a π-type high resistance layer, 4 is a p-type diffusion region surrounding the n-type cathode region 5, 6 is a cathode electrode,
7 is an n-type gate region, 8 is a gate electrode, 9 is a p-type anode region, 10 is an anode electrode, and 11 is a polysilicon substrate electrode. An n-type gate 7 and a polysilicon substrate electrode 1 are provided in the π-type high resistance region 3.
A depletion layer is formed by the potential of 1, and a potential barrier is formed between the p-type anode region 9 and the p-type diffusion layer 4. The role of the p-type diffusion layer 4 is to prevent punch-through between the n-type cathode region 5 and the n-type gate region 7. A bipolar transistor is formed by an npπn junction between the n-type cathode 5, the p-base 4, the π-layer 3, and the n-type gate 7;
A junction type p-channel FET is formed between the anode 9, the n-gate 7, the π layer 3, and the p-base 4. When electrons are injected from the n-type gate 7, the height of the potential barrier formed in the π layer 3 directly under the n-gate 7 changes, so that the hole current from the p-anode 9 of the p-channel FET undergoes conductivity modulation. As a result, the p base 4 is charged and electron injection from the cathode 5 is also caused. This turns on the GDS. To turn off the GDS, a potential barrier can be created in the π layer 3 by applying a positive voltage to the n-type gate region 7. That is, the injection of holes from the p anode 9 is blocked, and the GDS is turned off. The one shown in Figure 14, in which two GDSs are connected in parallel with each other in opposite directions, has the feature of functioning as a bidirectional switch with the ability to cut off not only alternating current but also direct current at the gate electrode. There is. Regarding this kind of GDS, PWShackle et al.
500V Monolithic Bidirectional 2×2
Crosspoint Array”) 1980 I. Triple.
Int Solid-State Circuits, Proc. of the 1980 IEEE, pp. 170-171.
Conf． pp. 170-171) or by PWShackle et al.
“A New Bidirectional Solid-
State Switch for Telephone Loop Plant
Applications”) Proceedings of I.
triple. E Vol. 69, No. 3, March 1981, p. 292~
299 pages (Proceedings of the IEEE, Vol.69,
No. 3, March 1981, pp. 292-299).

Since GDS can turn on and off direct current or alternating current at the gate, a circuit format has also been proposed in which a bipolar phototransistor is connected to the gate electrode to turn it off using light. FIG. 15 is an example.

On the other hand, optical triaxes have also been proposed in which the triaxes are controlled by light. L. leiporedo (L.
“600V/5A Field Effect Transistor: Triggered Lateral Opto Triax”
Lateral Opto-Triac”), Technical Digest I.Triple.E, International Electronic Devices Conference, 1982, pp. 261-263 (Tech.Digest of
IEEE IEDM 1982, pp. 261-263)
An integrated structure with a MOS gate structure is shown. However, triaxes are used to control alternating current and cannot cut off direct current. or,
Conventional optical trigger and optical quench SI thyristors cannot be turned on and off by bidirectional light.

[Problems to be Solved by the Invention] Among conventional semiconductor bidirectional switches, no one has been proposed that turns on direct current and alternating current with light and turns them off with light. That is, triax controls alternating current signals, and although optical trigger systems and integrated device structures have been proposed, it has not been possible to control direct current signals using light. on the other hand,
GDS can switch direct current and alternating current in both directions, but the main switching method is to turn the gate on and off electrically, and some methods have also been proposed to turn it off using light. However, nothing has been proposed that turns on and off using light alone. There has also been no proposal for a direct trigger method that turns on the GDS with light.

[Structure of the Invention] [Means for Solving the Problems] In order to switch direct current and alternating current in both directions, the present invention uses a light-triggered/light-quenched electrostatic induction thyristor, which is a self-extinguishing power semiconductor device. One unit is a configuration or structure in which two (light trigger/light quench SI thyristors) are connected or integrated in antiparallel to each other. Light trigger/light quench
SI thyristors have the ability to turn on and off direct current using only light, so by connecting two thyristors with their anodes and cathodes in antiparallel or integrating them, it is possible to turn direct current and alternating current on and off in both directions. This results in a bidirectional optical switch that is turned on by light and turned off by light.

[Function] The configuration of the bidirectional optical switch according to the present invention is basically one unit consisting of two optical trigger/optical quench SI thyristors with their anodes and cathodes connected in antiparallel.

When turning on with light, there are two methods: a direct light trigger method that directly irradiates the SI thyristor with light, and a method that irradiates light onto a photosensitive element (trigger photosensitive element) that is connected or integrated to the gate of the SI thyristor. , S.I.
There is an amplification gate method that amplifies and drives the gate portion of a thyristor. As for the gates of the bidirectional switch according to the present invention, the gates of the two SI thyristors may be a common gate, or separate gates may be provided using separate photosensitive elements for amplification. The first photosensitive element may be an electrostatic induction phototransistor, an electrostatic induction photothyristor, a photothyristor, a bipolar transistor, a pin photodiode, a Schottky diode, an avalanche photodiode, a photoconductor, a heterojunction phototransistor, or Any element that is sensitive to light may be used, such as a bipolar photodarlington configuration, a photodarlington configuration using an electrostatic induction phototransistor, a pin-JFET, a pin-JSIT configuration, or the like. Preferably, it is high speed and highly sensitive.

When turning off with light, light is irradiated to another photosensitive element (quenching photosensitive element) connected or integrated with the gate of the SI thyristor, and the light is accumulated in the gate area of the SI thyristor that is in the on state. The two-way switch can be turned off by pulling out the carrier. The second photosensitive element may be the one described above as the first photosensitive element. First, bidirectionality is created by connecting the anodes and cathodes of the two optically triggered and optically quenched SI thyristors in antiparallel. That is, it becomes possible to control AC signals. With only one SI thyristor, signals with electrical polarity in one direction can be controlled, but by the action of the other SI thyristor, signals in the opposite direction can also be controlled. Furthermore, the SI thyristor's inherent ability to cut off direct current is demonstrated, making it possible to control alternating current signals with superimposed direct current components. For such bidirectional switches, it is possible to control the gates by light instead of electrically turning them on and off, which improves electrical separation between the control circuit and the signal switch, noise resistance, and peripheral control. It is superior in terms of circuit simplification. The optical trigger method is superior in that it switches on two thyristors at the same time. At the time of switch-off, only a light trigger to the quenching photosensitive element is required.

The bidirectional optical switch according to the present invention can switch DC or AC signals in both directions using only light.
This allows you to perform the action of switching off. The light-triggered/light-quenched SI thyristor, which is a component of the present invention, is described in the paper by the present inventors, Nishizawa, Tamamushi, and Nonaka, "Light-controllable thyristor: Light-triggered and light-quenchable electrostatic induction light thyristor. ” 1984 International Solid State Devices and Materials Conference pp. 321-324 (J. Nishizawa, T.
Tamamushi and K.Nonaka“Totally Light”
Controlled Thyristor−Optically Triggerable
and Optically Quenchable Static Induction
Photo−Thyristor”Proc.of the 1984 Int.Conf.
on Solide−State Devices and Materials
(ICSSDM1984) pp.321-324).

[Embodiment] FIG. 1 shows another embodiment of the bidirectional optical switch according to the present invention, in which a shows an example of a circuit configuration and b shows an example of operating waveforms. In Fig. 1, SI thyristors 12 and 1
Another photosensitive element 2 connected to the gate terminal of 3
The SI thyristors 12 and 13 are made conductive at the same time by simultaneously applying optical trigger pulses LT14 and LT15 to 0 and LT21, respectively. An example is shown in which p-channel electrostatic induction phototransistors 20 and 21 are used as optical trigger elements. With the configuration of this embodiment, the turn-on extension time can be shortened and the operation speed can be increased compared to the case where the SI thyristor is directly triggered by light, but it is complicated because the number of components increases. FIG. 1b shows an example of operating waveforms.

FIG. 2a shows an example of a circuit configuration of a bidirectional optical switch according to the present invention, and FIG. 2b shows an example of operating waveforms of the bidirectional optical switch according to the present invention. light triggerable
The cathode and anode terminals, which are the main electrodes of the SI thyristors 12 and 13, are connected to the T1 and T2 terminals in antiparallel fashion, respectively. Further, in this example, p-channel electrostatic induction phototransistors 16 and 17 are connected to the gate terminals as quenching photosensitive elements, respectively.

The trigger light pulses LT14 and LT15 are simultaneously applied to the SI thyristors 12 and 13, respectively.
This causes bidirectional conduction between the T1 terminal and the T2 terminal.

Next, when the quenching light pulses LQ18 and 19 are simultaneously applied to the quenching p-channel electrostatic induction phototransistors 16 and 17, the carriers accumulated in the gate terminals of the SI thyristors 12 and 13 in the on state are removed. p
Since the discharge occurs through the channel SI phototransistors 16 and 17, the SI thyristors 12 and 13 are turned off at the same time.

FIG. 2b shows how the AC signal at the T1 terminal (a DC component may be superimposed) is propagated to the T2 terminal only between the trigger pulse LT and the quench pulse LQ.

In the embodiments shown in FIGS. 1 and 2, the gates of two SI thyristors connected in an antiparallel manner are configured as separate terminals, but
For simplicity, they may be connected in common. At this time, one of the quenching photosensitive elements 16 and 17 shown in FIG. 1 is omitted and simplified. Similarly, the trigger photosensitive element 20 in FIG.
Alternatively, one of 21 can also be omitted.

Furthermore, the photosensitive elements 16, 17, 20, 21 shown in the embodiments of FIGS. 1 and 2 are not limited to p-channel SI phototransistors, but may be SI photothyristors, bipolar phototransistors, etc., as described above. Any material that is sensitive to light may be used.

In addition, the two
The SI thyristor and other photosensitive elements only need to be electrically connected, and may be integrated.

There are also two types of SI thyristors: single gate type and double gate type. The double gate type has two gates in terms of structure, including a first gate that controls electron injection from the cathode and a second gate that also controls hole injection from the anode. Although the embodiments shown in Fig. 1 and Fig. 2 show a single gate type SI thyristor, the present invention also includes a bidirectional optical switch in which double gate type SI thyristors are connected in antiparallel and turned on and off only by light. include. There are also SI thyristors in which only one of the first gate or the second gate is used as a gate terminal, and the other gate is left in a floating state. In particular, double-gate type SI with a configuration in which only the second gate is used as a gate and the first gate is left in a floating state.
In the case of a thyristor, the polarity of the potential when the gate signal is turned on and off is opposite to that when only the first gate is used. In FIG. 1, the (-) sign of the main electrodes of the quench photosensitive elements 16 and 17 becomes a (+) sign in this case. Further, in FIG. 2, the (+) sign of the main electrodes of the trigger photosensitive elements 20, 21 becomes a (-) sign.

3 to 5 show embodiments of the bidirectional optical switch according to the present invention in a vertically integrated configuration,
FIG. 6 to FIG. 13 show an embodiment in a horizontal integrated configuration. Figure 3 is an example of two buried-gate single-gate SI thyristors integrated in antiparallel, and a quench p-channel SI phototransistor is integrated in the gate of each thyristor. . The first SI thyristor is formed from an n ⁺ cathode region 33, a p ⁺ buried gate region 30, an ^n- high resistance layer 32, a p ⁺ anode region 35, and the second SI thyristor is formed from an n ⁺ cathode region 34, a p ⁺ buried gate region 31,
It is formed of an n ^- high resistance layer 32 and a p ⁺ anode region 36 . The electrode portions 56 and 58 to the n ⁺ cathode regions 33 and 34 are connected to the trigger light pulse LT.
47, 48 and entry windows 57, 59 are formed. The two SI thyristors have a common cathode electrode 56 and an anode electrode 55 so that their main electrodes are connected in reverse parallel to each other, and a common cathode electrode 58 and an anode electrode 60, respectively, and are connected to the main terminals T1 and T2 of the bidirectional switch, respectively. It is becoming. A buried layer 301 common to the p ⁺ gate region 30 serves as one of the main electrodes of the quenching photosensitive element,
A p ^- channel SI phototransistor is formed between the p-channel, layer 38p ⁺ main electrode region 42, and n ⁺ gate region 41. Similarly, p ⁺ buried layer 311, p ^- channel layer 40, p ⁺ main electrode region 5
Another quenching p-channel SI phototransistor is formed between the 0 and n ⁺ gates 51.
Each quenching SI phototransistor is irradiated with quenching light pulses LQ46 and 49. 460,470,480,4
90 are optical pulses LQ46, LT47, LT respectively
48, an optical fiber introducing LQ49 is shown. Of course, any means for introducing light may be used. 43 and 44 indicate the gate electrode and main electrode of the quenching SI phototransistor. Also 52 and 53
are also the gate electrode and main electrode of another quenching SI phototransistor. The electrodes 43, 44, 52, and 53 may be configured to partially include a transparent electrode. 37 and 39 are n ^- high resistance layers.
61 and 62 indicate separation areas. Further, 400 indicates an insulating layer.

The circuit configuration of the embodiment of FIG. 3 is shown in FIG. 1a.

FIG. 4 shows an example of a vertically integrated structure of a bidirectional optical switch using a planar gate type single gate SI thyristor. P ⁺ gate regions 30, 31 and n ⁺ cathode regions 33, 34 are formed on the same plane, respectively. Further, 300 and 310 are gate electrodes to the p ⁺ gate regions 30 and 31, respectively. electrode 30
It is desirable that 0, 56, 310, and 58 partially include a transparent electrode. Other areas overlap with those of the embodiment shown in FIG. 3, so their explanation will be omitted.

FIG. 5 shows an example of a vertically integrated structure of a bidirectional optical switch using a cut-gate SI thyristor. A cut is made between each of the gate regions 30, 31 and cathode regions 33, 34 of the SI thyristor. Other parts are the same as those of the embodiment shown in FIGS. 3 and 4, so their explanation will be omitted.

In the embodiments shown in FIGS. 3 to 5, a structure is shown in which the quenching photosensitive element is integrated, but it is clear that the triggering photosensitive element can also be integrated with a similar structure.

FIG. 6 shows an example of a horizontally integrated bidirectional optical switch according to the present invention. Photo-triggerable SI is formed in high-resistance semiconductor layers 72 and 73 formed in an island shape in polysilicon 70 with an insulating layer 71 interposed therebetween.
A thyristor is formed. 77 and 76 are
The n ⁺ cathode region is shown, and 79 and 81 are the p ⁺ anode regions. The SI thyristor shown here is a double gate type with two gate regions. That is, the p ⁺ gate region 74 controls electron injection from the n ⁺ cathode region 77, and the p ⁺
n ⁺ controlling hole injection from anode region 79
This is the gate region 78. Although the p ⁺ gate region 74 of the first gate is in a floating state, it has a normally-off SIT gate structure. A potential barrier is formed in the high resistance layer 72 by the potentials of the n ⁺ gate region 78 of the second gate and the polysilicon layer 70 . Similarly, the p ⁺ gate region 75 is the first gate of another thyristor, and the n ⁺ gate region 80 is the second gate.
It is a gate. Furthermore, to provide bidirectionality, the cathode electrode 84 of the first thyristor is common to the anode electrode 82 of the second thyristor, and the anode electrode 85 of the first thyristor is common to the cathode electrode 83 of the second thyristor. connected to,
The T1 terminal and T2 terminal serve as the main terminals of the bidirectional optical switch, respectively. In the embodiment of FIG. 6, gate electrodes 86 and 87 are common. 6th
The figure shows an example of directly triggering two optically triggerable SI thyristors, with optical fibers 90,
Optical trigger pulse LT92 introduced by 91,
The two thyristors are made conductive at the same time by LT93. Of the electron-hole pairs generated in the high resistance layers 72 and 73, electrons are accumulated in the n ⁺ gate regions 78 and 80, and holes are accumulated in the p ⁺ gate regions 74 and 75. As carriers accumulate in these p ⁺ gates and n ⁺ gates, the n ⁺ cathode region 7
Electrons are caused to be injected from 7 and 76 toward high resistance layers 72 and 73, respectively, while holes are injected from p ⁺ anode regions 79 and 81, respectively.
That is, both electron-hole pairs generated by the optical trigger work effectively to turn on the thyristor. The potential barrier generated in the high-resistance channel in the off state is
The SI thyristor photo-turns on when the gate potential exceeds the turn-on threshold voltage, which is pulled down by the electrostatic induction effect by the gates along with the accumulation in the p ⁺ gates 74, 75 and n ⁺ gates 78, 80. It has been shown that the optical trigger sensitivity of the SIT gate structure is much greater than that of conventional bipolar-based structures, and the turn-on threshold is also lower. Although the quenching photosensitive element is not shown in FIG. 6, it is of course possible to connect it to the common gate terminal G2 from the outside or to integrate it as described later.

FIG. 7 shows another horizontally integrated structure example of a bidirectional optical switch according to the present invention. However, in each part, parts common to those in FIG. 6 are indicated by the same numbers. FIG. 7 shows an integrated structure in which two optically triggerable double-gate SI thyristors are connected in antiparallel, similar to that in ^FIG . and 75
The electrodes 88 and 89 are commonly connected and used.
In other words, the first gate p ⁺ regions 74 and 75 for controlling the injection of electrons from the cathode n ⁺ regions 77 and 76 of the SI thyristor serve as the common gate of the bidirectional optical switch, and the second gate serves as the common gate of the bidirectional optical switch. The n ⁺ regions 78 and 80 are in a floating state as a normally-off SIT gate structure. In a double gate type SI thyristor, only the first gate may be used as a gate, or only the second gate may be used as a gate as in the embodiment shown in FIG. 6 described above. Naturally, the wiring becomes complicated, but both the first and second gates may be used and a quenching photosensitive element may be connected or integrated with each of them.

FIG. 8 shows an integrated structure of an SI thyristor portion and an n-channel SI phototransistor for quenching, and is an embodiment in which a photosensitive element for quenching is further integrated in the embodiment of FIG. 6. Parts common to each part in FIG. 6 are indicated by the same numerals.
In FIG. 8, an n-channel SI phototransistor is formed in a high-resistance semiconductor region 100 formed in an island shape in a polysilicon layer 70 with an insulating layer 71 interposed therebetween. The n ⁺ region 103 represents one of the main electrodes and is commonly connected to the n ⁺ gate electrode 86 of the SI thyristor via the electrode 108 . p ⁺ area 10
2 indicates the gate of the quenching SI phototransistor, and n ⁺ regions 104 and 105 indicate the other main electrode. 107 is its gate electrode, and 106 is its main electrode terminal. In order to turn off the bidirectional optical switch configured as shown in Fig. 6 using light, it is sufficient to turn off the SI thyristor that is in the on state.
A light quench pulse is introduced into the quenching SI phototransistor shown in FIG. 8 by an optical fiber 94.
All you have to do is turn on the light using LQ95. Among the electron-hole pairs generated in the high-resistance layer by the optical quench pulse LQ95, the hole is in the p ⁺ gate region 10.
2, the potential of the p ⁺ gate 102 increases in the positive direction, and the potential of the n ⁺ region 103 increases.
Electrons will flow more toward the n ⁺ regions 105 and 104. That is, the electrons accumulated in the n ⁺ gate portion 78 of the bidirectional optical switch in the on state are discharged through the quenching SI phototransistor, and the SI thyristor portion is turned off by the light. In other words, the bidirectional optical switch is also turned off.

FIG. 9 shows an integrated embodiment in which the gate portion of the SI thyristor is triggered by amplified light using another trigger photosensitive element as described in the embodiment of FIG. Combining this with FIG. 8 corresponds to integrating the embodiment of FIG. 2. However, the gate of SI thyristor is n ⁺ gate 7
8, an n-channel SI phototransistor is used as the trigger photosensitive element. In FIG. 9, n ⁺ region 111 is shared with n gate region 78 of the SI thyristor via electrodes 86 and 71. In FIG. p ⁺ gate 110, high resistance layer 101, n ⁺
Regions 113 and 112 are the gate region, channel region, and main electrode region of the SI phototransistor, respectively. 115 is a gate electrode, 114 is a main electrode, and is biased in the (-) sign direction. When the n-channel SI phototransistor is turned on by the trigger light pulse LT97 introduced by the optical fiber 96, a negative voltage is applied to the n ⁺ gate 78 portion of the SI thyristor, so that the SI thyristor is indirectly exposed to light. That's what triggers it.

8 and 9 correspond to an embodiment in which the second gate of the SI thyristor is the common gate of the bidirectional optical switch, but similarly, the first gate of the SI thyristor is the common gate of the bidirectional optical switch. FIGS. 10 and 11 show integrated embodiments corresponding to this case.

FIG. 10 is an example of integrating the SI thyristor portion shown in FIG. 7 with a p-channel SI phototransistor as a quenching photosensitive element. Parts common to those in FIG. 7 are indicated by the same numbers. In FIG. 10, p ⁺ region 203 represents one of the main electrodes of the quench p-channel SI phototransistor, and is shared with p ⁺ gate region 74 of the SI thyristor portion via electrodes 88 and 208. N ⁺ gate 202 indicates the gate region of the SI phototransistor, 200 is a high resistance channel layer, and p ⁺ regions 205 and 204 are other main electrode regions. 207 is a gate electrode, and 206 is a main electrode terminal. When the bidirectional optical switch is in the on-electrode, the holes accumulated in the p ⁺ gate region 74 are discharged toward the p ⁺ region 204 when the quenching SI phototransistor is turned on by light, so that they are not turned off by light. That is why it is done.

FIG. 11 similarly shows an example in which a p-channel SI phototransistor is integrated into a bidirectional optical switch as a trigger photosensitive element. Parts common to those in FIG. 7 are indicated by the same numbers. p for trigger
Channel SI phototransistor has p ⁺ region 21
1 as one of the main electrodes, p ⁺ regions 213 and 21
2 as the other main electrode, and the n ⁺ region 21
0 indicates a gate, and 201 indicates a high resistance channel layer. 215 is the gate electrode, 216 is the p ⁺ region 21
1, which is common to the electrode 88 of the gate region 74 of the SI thyristor portion. 214
indicates the other electrode of the main electrode. When the SI phototransistor is turned on by the optical trigger pulse LT97 introduced by the optical fiber 96, the p ⁺ gate region 74 of the SI thyristor portion is indirectly optically triggered.

FIG. 12 shows another horizontal integrated structure of a bidirectional optical switch according to the invention. Since it is structurally similar to FIG. 6, common parts are indicated by the same numbers. The major difference from the structure in Figure 6 is
The difference is that n ⁺ gate regions 78 and 80 for controlling hole injection from p ⁺ anode regions 79 and 81 are not formed to surround p ⁺ regions 79 and 81. The n ⁺ gate regions 78 and 80 are formed deeper than in the structure of FIG. Depending on the potential state of the n ⁺ gate regions 78, 80 and the polysilicon layer 70, the p ⁺ anode 79,
The diffusion depths of the n ⁺ layers 78 and 80 and the thicknesses of the high resistance layers 72 and 73 are selected so that a potential barrier against holes injected from the n + layers 81 is formed. In this way, there is no difference in operation from the embodiment shown in FIG.

FIG. 13 similarly shows the first p ⁺ gate 74,
12 shows an embodiment in which a structure similar to that of the embodiment shown in FIG. 12 is introduced in the section 75. Common parts are indicated by the same numbers.

Also in the embodiments shown in FIGS. 12 and 13, it is easy to integrate the quench photosensitive element or the trigger photosensitive element.

Although the SI thyristors constituting the bidirectional optical switches shown in FIGS. 6 to 13 are shown with a planar gate structure, the structure is not limited to this.
It may be formed using an SI thyristor with a buried gate structure, a cut gate structure, or
An SI thyristor with a MOS/MIS gate structure may also be used. Furthermore, as described above, the photosensitive element for photo-triggering or photo-quenching is not limited to the SI phototransistor.

Further, in the embodiments shown in FIGS. 6 to 13, examples are shown in which dielectric isolation technology is used, but it is also possible to use a combination of pn junction isolation, V-groove isolation, U-groove isolation, etc. Good too.

[Effects of the Invention] The bidirectional optical switch according to the present invention can conduct AC or DC signals in both directions using light,
Since the control circuit and the bidirectional optical switch can be completely electrically isolated from each other, it is possible to completely electrically isolate the control circuit and the bidirectional optical switch. Since it is composed of SI thyristors, the optical trigger sensitivity is high and high-speed triggering is also possible. Furthermore, since it can be turned off by light, the peripheral control circuitry is extremely simplified and the number of components in the overall system is reduced. The speed of turning off by light is also fast. The signal to be switched can range from relatively low-power alternating current or direct current to high-power alternating current or direct current, and can be turned on and off in both directions using only light.
Furthermore, multiplexing can also be achieved by integrating.
In particular, a bidirectional switch for a telephone circuit network is required to have an AC current of ±400V including a DC component and a current of several A, but the bidirectional optical switch that uses the SI thyristor according to the present invention as a component easily satisfies the required specifications. ing. SI thyristors also have the characteristic of being particularly resistant to large current surges.

Also, since it uses an SI thyristor as a component,
The switching speed can be increased, and while the electrical turn-off time of conventional GDS is said to be 13μs, the bidirectional optical switch according to the present invention can be turned off at an optical trigger of about 500V-1A. ,
Both light quench times are less than 1μs. Furthermore, the forward voltage drop in the turn-on state
It has been measured to be 0.75V at 100A/cm ² and 1.3V at 1000A/cm ² , which is lower than GDS. In other words, both switching loss and conduction loss can be kept low. In terms of frequency characteristics, the telephone line network has a frequency of around 60Hz, so the efficiency of the switch is 99.9%.
That's all. If you increase the frequency further to 10kHz
It can also be used with an efficiency of over 99%.

The bidirectional optical switch according to the present invention can be turned on and off using only light in both directions, direct current or alternating current, and is small due to the high speed, low loss, high efficiency, and low noise properties of SI thyristors. It can handle not only electric power but also large amounts of electric power, making it extremely valuable industrially.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of a bidirectional optical switch according to the present invention, in which a is a circuit type, b is an example of an operating waveform, and a second
The figure shows another embodiment of the bidirectional optical switch according to the present invention, in which a is the circuit type, b is an example of the corresponding operating waveform, and FIG. 3 is a vertical bidirectional optical switch using a buried gate type SI thyristor. An example of an integrated structure, FIG. 4 shows an example of a vertical integrated structure using a planar gate type SI thyristor, and FIG. 5 shows an example of a vertical integrated structure using a notch gate type SI thyristor. 6 to 13 relate to embodiments of the bidirectional optical switch of the present invention having a horizontal integrated structure.
The figure shows an integrated structure of a bidirectional optical switch using a horizontal SI thyristor with the second gate as a common gate, FIG. 7 shows an integrated structure of a bidirectional optical switch using a horizontal SI thyristor with the first gate as a common gate, The figure shows an example of a structure in which an n-channel SI phototransistor for quenching is further integrated into the embodiment of FIG. 6, and FIG. 9 is an example of a structure in which an n-channel SI phototransistor for triggering is further integrated in the embodiment of FIG. 6. 1st
Fig. 0 shows an example of a structure in which a p-channel SI phototransistor for quenching is further integrated into the embodiment shown in Fig. 7, and Fig. 11 shows an example of a structure in which a p-channel SI phototransistor for triggering is further integrated in the embodiment shown in Fig. 7. , Fig. 12 shows an example of the structure of a bidirectional optical switch with a modified structure of the second gate part of the SI thyristor.
The figure shows an example of the structure of a bidirectional optical switch with a modified structure of the first gate part of the SI thyristor, Fig. 14 shows a part of the structure of a gated diode switch GDS as a conventional example, and Fig. 15 shows an optical signal. An example of a conventional GDS off-circuit using hν is shown. 12, 13... SI thyristor or optically triggerable SI thyristor, 14, 15... Trigger light pulse, 16, 17... SI phototransistor for quenching, 18, 19... Quench light pulse, 20, 21
...SI phototransistor for trigger.

Claims (1)

[Claims] 1. High-resistance semiconductor substrate 32 having a first conductivity type.
a first gate region consisting of high impurity concentration regions 30, 301 of a second conductivity type near the surface of the semiconductor substrate; and a first gate region of the semiconductor substrate near the first gate region. a first cathode region 33 with high impurity concentration having a second gate region 3 consisting of one electrostatic induction thyristor and a high impurity concentration region of a second conductivity type near the back surface of the semiconductor substrate 32;
1,311, a second cathode region 34 of high impurity having the first conductivity type on the back surface of the semiconductor substrate near the second gate region, and a high impurity concentration of the second conductivity type on the surface of the semiconductor substrate 32. a second electrostatic induction thyristor comprising a second anode region 36; a first drain region 301 of a second conductivity type and having a high impurity concentration in a region shared with the first gate region;
a first drain region of a second conductivity type above the first drain region;
a low impurity concentration region 38 of the first low impurity concentration region, a second conductivity type high impurity concentration first source region 42 of a part of the surface of the first low impurity concentration region, and substantially surrounding the first source region. a first photosensitive element comprising a third gate region 41 of a first conductivity type with a high impurity concentration formed as shown in FIG. a second drain region with an impurity concentration;
A second low impurity concentration region 40 of a second conductivity type below the second drain region, and a high impurity concentration region of a second conductivity type in a portion of the lower surface of the second low impurity concentration region. a second photosensitive element comprising a second source region 50 and a fourth gate region 51 of a first conductivity type and high impurity concentration formed so as to substantially surround the second source region; The first and second electrostatic induction thyristors are comprised of a light irradiation means and a light trigger light source; a light irradiation means and a light trigger light source for the first and second photosensitive elements; the cathode region and the second anode region are connected to form a first main terminal; the first anode region and the second cathode region are connected to form a second terminal;
The first and second electrostatic induction thyristors are made conductive by irradiation of light to both or either one of them, and are interrupted by irradiation of light to the first and second photosensitive elements. A two-way optical switch that can turn on and off direct current and alternating current. 2 High-resistance semiconductor substrate 32 having a first conductivity type
and a second conductivity type high impurity concentration first gate region 30, 301 near the surface of the high resistance semiconductor substrate.
a first cathode region 33 having a first conductivity type and a high impurity concentration on the surface of the semiconductor substrate near the first gate region; and a second cathode region 33 on the back surface of the semiconductor substrate opposite to the first cathode region. A first electrostatic induction thyristor comprising a second anode region 35 of a conductivity type with high impurity concentration; and a second gate comprising a high impurity concentration region of a second conductivity type near the back surface of the semiconductor substrate 32. Area 3
1,311, a second cathode region 34 consisting of a high impurity concentration layer having a first conductivity type on the back surface of the semiconductor substrate near the second gate region;
a second electrostatic induction thyristor comprising: a second anode region 36 made of a second conductivity type high impurity concentration on the surface of the semiconductor substrate 32 facing the cathode region; and a region shared with the first gate region. a first drain region 301 of a second conductivity type with a high impurity concentration, a first low impurity concentration region 38 of a second conductivity type of the drain region, and a part of the surface of the first low impurity concentration region. a first source region 42 having a high impurity concentration of a second conductivity type, and a third source region 42 having a high impurity concentration having a first conductivity type formed so as to substantially surround the second source region 42; A first photosensitive element having a gate region 41 and a second drain region having a high impurity concentration of a second conductivity type in a shared region with the second gate region 311; A second low impurity concentration region 40 of a second conductivity type below the drain region, and a high impurity concentration second source region of a second conductivity type that is part of the lower surface of the second low impurity concentration region. 50, and a fourth gate region 5 having a first conductivity type and having a high impurity concentration and formed so as to substantially surround the second source region.
1, and a third photosensitive element whose electrode region is a region shared with the first gate region, and whose main electrode region is a region shared with the second gate region. a fourth photosensitive element, a means for irradiating light to the first and second photosensitive elements and a quenching light source, a means for irradiating light to the third and fourth photosensitive elements and a light source for triggering. The first cathode region and the second anode region are connected to form a first main terminal, the first anode region and the second cathode region are connected, and a second main terminal is formed. forming the main terminal of
Conductive by light irradiation to both or one of the third and fourth photosensitive elements, and cut off by light irradiation to the first and second photosensitive elements, A two-way switch that can turn DC and AC on and off in layers. 3. A semiconductor substrate 70, and a first island region 72, a second island region 73, and a third island region formed on a part of one main surface of the semiconductor substrate with an insulating film separation region 71 interposed therebetween.
island regions 100, 101, 200, 201, and a fourth island region, and a first cathode region 77 and a first second gate region of the first conductivity type formed on the surface of the first island region. 78, the first of the second conductivity type
a first double-gate static induction thyristor comprising an anode region 79 and a first gate region 74; and a second cathode region of a first conductivity type formed on the surface of the second island region. 76 and 2nd
a second double gate electrostatic induction thyristor comprising a second gate region 80 of a second conductivity type, a second anode region 81 of a second conductivity type and a second first gate region 75; a first electrostatic induction phototransistor having a main electrode region connected to either the first first gate region or the first second gate region formed in the fourth island region; irradiation of light to either the second first gate region or the second second gate region, the main electrode second static induction phototransistor, and the first and second double gate static induction thyristors; The first anode region and the second cathode region are connected to each other. The first cathode region and the second anode region are connected to form a second main terminal, and direct current and alternating current are turned on and off in both directions by turning on and off the trigger light source. A two-way light switch. 4. A semiconductor substrate 70, and a first island region 72, a second island region 73, and a third island region 100 formed on a part of one main surface of the semiconductor substrate via an insulating film separation region 71. , 101, 200, 201, and a fourth island region, and a first cathode region 77 of the first conductivity type formed on the surface of the first island region.
and a first double gate static induction thyristor comprising a first second gate region 78, a first anode region 79 of a second conductivity type and a first first gate region 74; A second cathode region 76 and a second gate region 80 of the first conductivity type formed in the island region, a second anode region 81 of the second conductivity type and a second first gate region 75
a second double-gate static induction thyristor comprising: a main electrode connected to either the first gate region or the first second gate region formed in the third island region; a first electrostatic induction phototransistor formed in the fourth island region and having a main electrode connected to either the second first gate region or the second second gate region; an inductive phototransistor, a first trigger photosensitive element in which a main electrode region is connected to either the first gate region of the first or the second gate region of the first, and the second first gate; or the second second gate region and the main electrode region, a second trigger photosensitive element, a light irradiation means for the second trigger photosensitive element, a trigger light source, and the first trigger photosensitive element. , comprises a light irradiation means for the second electrostatic induction phototransistor and a quenching light source, the first anode region and the second cathode region are connected to form a first main terminal, A bidirectional optical switch having a first cathode region and a second main terminal, and bidirectionally turning on and off direct current and alternating current by turning on and off the trigger light source and the quench light source.