JPH0629518A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device wherein it can avoid that a chip area is increased, it is suitable for being applied to a power electronics circuit and it is of a good-performance integration type. CONSTITUTION:A semiconductor device is constituted in the following manner: a cathode region and a gate region are formed on the surface part on one side of a semiconductor substrate 2; a cathode electrode 21 and a gate electrode 22 are formed on the semiconductor substrate; the gate electrode and the cathode electrode are composed respectively of a trunk in which a branch part and a branch part are connected; and a static-induction semiconductor element 3 wherein the electrodes come into contact by the branch parts and the electrodes are led out by the trunk part is provided. A first-conductivity-type junction isolation region 16 insulated and isolated from the circumference by interposing a second-conductivity-type semiconductor layer is formed at the lower part of the trunk of at least one electrode out of both electrodes on the semiconductor substrate; a semiconductor element 4 different from the static-induction semiconductor element is formed in the junction isolation region.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated type semiconductor device suitable for application to power electronic circuits.

[0002]

2. Description of the Related Art Static induction thyristors are suitable as power devices. If a semiconductor element (for example, an element such as a transistor for controlling the electrostatic induction thyristor) is also provided separately from the thyristor on the semiconductor substrate on which the electrostatic induction thyristor is provided, it is very easy to use and practical. Sex will be enhanced.

That is, like the semiconductor device 31 shown in FIG. 3, the electrostatic induction thyristor 33 is formed on one semiconductor substrate 32.
At the same time, the transistor 34 is provided. The electrostatic induction thyristor 33 of this semiconductor device 31 is a semiconductor substrate 32.
In the surface portion on the front side of the cathode region 4, an n ⁺ type (first conductivity type) cathode region 41 having a high impurity concentration and ap ⁺ type (second conductivity type) gate region 42 having a high impurity concentration are formed.
1 is formed so as to be sandwiched between the gate regions 42, and a cathode electrode 51 that contacts the cathode region 41 and a gate electrode 52 that contacts the gate region 42 are formed on the semiconductor substrate 32. The surface portion on the back side of the semiconductor substrate 32 has a p ⁺ -type anode region 43.
And the anode electrode (not shown) comes to the surface. Then, the cathode region 4 in the semiconductor substrate 32
A region between 1 and the anode region 43 is an n ⁻ type high specific resistance region 44 which is a base region.

On the other hand, the transistor 34 which is another semiconductor element in the semiconductor device 31 has an n ^-- type junction isolation region 3
6 is provided. As shown in FIG. 4, the semiconductor device 3
1 is viewed from above, the formation area A of the electrostatic induction thyristor 33
Next to that, the formation region B of the transistor 34, that is, the junction isolation region 36 is provided side by side. The junction isolation region 36 is insulated and isolated from the surroundings by the interposition of the p ⁺ type semiconductor layer 35. In the junction isolation region 36, a p type base region 45, an n ⁺ type emitter region 46 and a collector region 47 are provided. Are formed, and electrodes 55, 56, 57 are formed in contact with the respective regions.

However, the above semiconductor device cannot be said to be sufficient even if the size and cost thereof are reduced to some extent. The chip area increases and the number of wafers that can be taken per wafer decreases, so that the yield decreases and it is not possible to achieve a substantial cost reduction. Chip area is static induction thyristor 3
The area of the formation area A of 3 is increased by the area of the formation area B of the transistor 34, and the area is considerably increased.

[0006]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides an integrated type semiconductor device which is capable of avoiding an increase in chip area and is suitable for application to power electronic circuits. Is an issue.

[0007]

In order to solve the above-mentioned problems, a semiconductor device according to the present invention has a cathode region of a first conductivity type and a gate region of a second conductivity type on a surface portion on one side of a semiconductor substrate. Is formed such that the cathode region is sandwiched between the gate regions, and a cathode electrode that contacts the cathode region and a gate electrode that contacts the gate region are formed on the semiconductor substrate. Each of the cathode electrodes is composed of a branch portion and a trunk portion to which the branch portion is connected, and in a configuration including an electrostatic induction semiconductor element in which electrode contact is made by the branch portion and electrode is led by the trunk portion, A semiconductor layer of the second conductivity type is provided at a position below a trunk portion of at least one of the electrodes on the semiconductor substrate so as to be insulated from the surroundings. Have junction isolation region of the first conductivity type is provided and be provided with a separate semiconductor element from the above static induction semiconductor device in this junction isolation region.

The electrostatic induction semiconductor element of the semiconductor device of the present invention may be an electrostatic induction thyristor, but is not limited to this and may be an electrostatic induction transistor. However, in the case of a transistor, the cathode is usually called the source and the anode is called the drain. Examples of another semiconductor element provided in the junction isolation region below the trunk of at least one of the electrodes of the semiconductor device of the present invention include an element such as a bipolar transistor, a field effect transistor, and a diode. It is provided in the form of a single or a plurality of coexisting.

Of course, in the present invention, when the first conductivity type is n-type, the second conductivity type is p-type, and conversely, when the first conductivity type is p-type, the second conductivity type is n-type. Becomes

[0010]

The semiconductor device of the present invention is provided with the electrostatic induction semiconductor element suitable for the power device in which the cathode electrode is drawn out by the trunk portion capable of sufficiently flowing the current.
Since it also has a semiconductor element other than the static induction semiconductor element, it is suitable for application to power electronic circuits.

In addition, the semiconductor element other than the electrostatic induction semiconductor element in the semiconductor device of the present invention is insulated and separated from the electrostatic induction semiconductor element having a large capacitance by the junction separation, so that the interference between the two elements is prevented. The performance is good because it is prevented. And, most characteristically, in the semiconductor device according to the present invention, the junction isolation region in which the semiconductor element different from the electrostatic induction semiconductor device is provided is a trunk portion of the cathode electrode or the gate electrode which has conventionally been a dead space. Is provided by utilizing the semiconductor substrate portion below. Therefore, the chip area does not need to be increased, and the number of wafers that can be obtained per wafer is almost the same, and the cost can be directly reduced by the amount of integration.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing the configuration of a main part of a semiconductor device according to an embodiment, and FIG. 2 is a plan view of a cathode electrode and a gate electrode provided on a semiconductor substrate of the semiconductor device according to the embodiment. As shown in FIG. 1, the semiconductor device 1 of the embodiment includes a bipolar transistor 4 on one semiconductor substrate 2 together with an electrostatic induction thyristor 3.

The electrostatic induction thyristor 3 of this semiconductor device 1
Has a high impurity concentration on the front surface of the semiconductor substrate 2.
I n⁺Type (first conductivity type) cathode region 11 and impurity concentration
High degree p⁺Type (second conductivity type) gate region 12
Formed so that the cathode region 11 is sandwiched between the gate regions 12.
The semiconductor substrate 2 and the cathode region.
Cathode electrode 21 and gate region contacting region 11
A gate electrode 22 that contacts 12 is formed
On the other hand, the surface portion on the back side of the semiconductor substrate 2 is p ⁺Type of
An anode region 14 is formed, and an anode is formed on the surface thereof.
An electrode (not shown) comes. And on the semiconductor substrate 2
Between the cathode region 11 and the anode region 13
Area n^-This is the high resistivity region 15 of the mold.

The bipolar transistor 4, which is another semiconductor element in the semiconductor device 1, is provided in the n ^-- type junction isolation region 16. This junction isolation region 16 is p ⁺
It is insulated from the surroundings by the interposition of the semiconductor layer 17 of the mold. Then, in the junction isolation region 16, a p-type base region 18, an n ⁺ -type emitter region 19 and a collector region 20 are formed, and electrodes 25, 26, 2 are respectively formed therein.
7 is in contact, and has a bipolar transistor configuration.

On the other hand, the cathode electrode 21 is composed of a branch portion 21a and a stem portion 21b to which the branch portion 21a is connected. The branch portion 21a contacts the cathode region 11, and current is collected in the stem portion 21b to form a bonding pad portion (shown in the figure). The electrode has a lead-out structure that leads to (omitted). On the other hand,
The gate electrode 22 is composed of a branch portion 22a and a trunk portion 22b to which the branch portion 22a is connected.
2 is in contact therewith, and the current is collected in the trunk portion 22b and led to a bonding pad portion (not shown).

Normally, a p ⁺ -type semiconductor layer 13 for maintaining the breakdown voltage is provided below the trunk portion 22b of the gate electrode 22 and may partially serve as a gate region.
^The trunk portion 22b is in direct contact with the ⁺ type semiconductor layer 13. On the other hand, conventionally, the trunk portion 21 of the cathode electrode 21 is
A junction isolation region 16 is formed below b, and the bipolar transistor 4 is formed therein. Conventionally, nothing is provided below the trunk portion 21b of the cathode electrode 21, and the Si bulk portion becomes a dead space. However, in the case of the semiconductor device of the present invention, the dead space is effectively used. It has become possible to reduce costs by avoiding an increase in chip area. Usually, after forming the bipolar transistor 4, an oxide film 9 is deposited and formed by vapor deposition or the like, and the trunk portion 21b of the cathode electrode 21 is formed thereon by the two-layer wiring technique.

Note that n ^{− on} both sides of the p ⁺ type semiconductor layer 17 are formed.
The n ^- type semiconductor layer on the junction isolation region 16 side is the collector region of the bipolar transistor, and the n ^- type semiconductor layer on the static induction thyristor 3 side is electrically isolated.
^{This is because the-} type semiconductor layer is the base region of the thyristor, and is not electrically conductive because it is not forward biased even in actual use.

The present invention is not limited to the above embodiment. For example, the junction isolation region 16 is the trunk portion 21 of the cathode electrode 21.
It may be provided below the trunk portion 22b of the gate electrode 22 or below the trunk portions 21b and 22b of the electrodes 21 and 22 instead of below the b portion. Of course, the gate electrode 2
It goes without saying that the p ⁺ type semiconductor layer 13 below the second trunk portion 22b is not formed at least at the position where the junction isolation region 16 is provided.

[0019]

The semiconductor device according to the present invention is suitable for the application of the power electronic circuit because it has the electrostatic induction semiconductor element suitable for the power device and also has another semiconductor element. Moreover, the semiconductor element different from the electrostatic induction semiconductor element has good performance because the interference between the elements is prevented by the junction separation, and in addition, the other semiconductor element does not increase the chip area. Therefore, a sufficient cost reduction can be expected, and therefore the semiconductor device of the present invention can be said to be very practical.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a main part of a semiconductor device of an example.

2 is a plan view showing a cathode electrode and a gate electrode provided on a semiconductor substrate of the semiconductor device of FIG.

FIG. 3 is a cross-sectional view showing a configuration of a main part of a conventional semiconductor device.

FIG. 4 is a plan view showing a state of the semiconductor device of FIG. 3 viewed from above.

DESCRIPTION OF SYMBOLS 1 semiconductor device 2 semiconductor substrate 3 electrostatic induction thyristor (electrostatic induction semiconductor element) 4 bipolar transistor (another semiconductor element) 21 cathode electrode 21a branch 21b trunk 22 gate electrode 22a branch 22b trunk

Claims (1)

[Claims] 1. A first conductivity type cathode region and a second conductivity type gate region are formed on a surface portion of one side of a semiconductor substrate such that the cathode region is sandwiched between the gate regions.
A cathode electrode contacting the cathode region and a gate electrode contacting the gate region are formed on the semiconductor substrate, and the gate electrode and the cathode electrode are connected to a branch portion and a branch portion, respectively. In a semiconductor device including an electrostatic induction semiconductor element, which comprises a trunk portion, the electrode contact is made at a branch portion, and the electrode is pulled out at the trunk portion, below a trunk portion of at least one of the electrodes on the semiconductor substrate. At the position, a first conductivity type junction isolation region is provided, which is insulated from the surroundings by interposing a second conductivity type semiconductor layer, and this junction isolation region is different from the electrostatic induction semiconductor element. A semiconductor device comprising a semiconductor element.