JPH1032176A - Etching method and method of manufacturing semiconductor device - Google Patents

Abstract

(57) Abstract: An InAlAs layer is etched to form InGaAs.
A highly selective etching method using an s layer as an etching stop layer is provided. SOLUTION: In a Cl ₂ gas atmosphere, a semiconductor sample on which InGaAs and InAlAs are laminated is provided with a wavelength of 193 nm.
nm, power density 20 mJ / cm ² below, or irradiated with light, or Cl ₂ in a mixed gas atmosphere of a gas and O ₂ gas, the wavelength 193nm in a semiconductor sample InGaAs and InAlAs are stacked, the power density of 13 mJ / cm ²
The following light is irradiated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for etching a semiconductor and a method for manufacturing a semiconductor device using the etching method.

[0002]

2. Description of the Related Art In recent years, research and development of devices using compound semiconductor materials have been actively conducted for the purpose of improving the performance of semiconductor devices. Semiconductor processing using the etching rate ratio (selectivity) of semiconductor layers having different compositions has been performed in order to reduce the performance variation of the semiconductor element. Was etched, and a semiconductor layer containing Al was used as an etching stop layer (hereinafter, referred to as forward selective etching).

[0003] In a semiconductor device, for example, a selective etching characteristic opposite to the selective etching characteristic such as HBT, that is, a semiconductor layer containing Al is etched, and a semiconductor layer containing no Al is etched. Some require etching technology (hereinafter, referred to as reverse selective etching) having an etching characteristic to serve as a stop layer, and development of a reverse selective etching technology has been desired.

An inverse selective etching technique for a GaAs / AlGaAs-based material is disclosed in Japanese Patent Application Laid-Open No. 7-263383, in which a halogen compound such as chlorine or fluorine is used as an etching gas and the power of pulse light is 30 mJ / c.
It is said that at m ² or more, etching proceeds faster with AlGaAs than with GaAs.

[0005]

As for the above-mentioned inverse selective etching, the material system is changed from the GaAs / AlGaAs system to a semiconductor material containing In and Ga / a material system of a semiconductor material containing In and Al, for example, In _y Ga _{1. -y} As (0 <y <
1, hereinafter simply referred to as InGaAs) / In _x Al _1-x
As (0 <x <1, hereinafter simply referred to as InAlAs)
When etching was performed using chlorine (Cl ₂ ) gas, the power density of the pulse light was 30 mJ / c.
m ² or more InGa etching rate of InAlAs is the
There has been a problem that the etching rate is only several times the etching rate of As and the magnitude of the selectivity is insufficient in practical use.

A first object of the present invention is to provide a semiconductor laminated film having a laminated structure of a semiconductor layer containing In and Al and a semiconductor layer containing In and Ga, which has a practically sufficiently high selection ratio. It is to provide an etching technique.

A second object of the present invention is an etching technique for selectively etching a semiconductor layer containing In and Ga in a semiconductor laminated film having a laminated structure of a semiconductor layer containing In and Al and a semiconductor layer containing In and Ga. A stacked structure in which a semiconductor film containing In and Ga and a semiconductor film containing In and Al are alternately stacked in a total of three or more layers by sequentially performing switching between the (selective etching technique) and the above-described reverse selective etching technique. It is an object of the present invention to provide a method for manufacturing a semiconductor device, which etches a semiconductor film having a good controllability.

[0008]

A first object of the present invention is to provide a sample in which a semiconductor laminated film having a laminated structure of a layer to be etched containing In and Al and an etching stop layer containing In and Ga is formed on a surface. Under the atmosphere of gas containing chlorine,
This can be achieved by irradiating light of 20 mJ / cm ² or less (hereinafter, referred to as first means).

A first object of the present invention is to provide a sample in which a semiconductor laminated film having a laminated structure of a layer to be etched containing In and Al and an etching stop layer containing In and Ga is formed on a surface of a sample containing chlorine gas. This can be achieved by irradiating light of 13 mJ / cm ² or less in a mixed gas atmosphere of a gas containing oxygen (hereinafter, referred to as a second means).

A second object of the present invention is to provide a sample in which a semiconductor laminated film having a structure in which a semiconductor layer containing In and Al and a semiconductor layer containing In and Ga are alternately laminated three or more layers is formed on the surface. When the semiconductor layer containing In and Ga is selectively etched, light is irradiated in a mixed gas atmosphere of a gas containing bromine and a gas containing fluorine to selectively etch the semiconductor layer containing In and Al. In this case, it can be achieved by using the first means or the second means.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a specific example of the etching method according to the present invention, an ArF excimer laser having a wavelength of about 193 nm in a chlorine gas atmosphere is applied to a sample on which a semiconductor laminated film having a laminated structure of an InGaAs layer and an InAlAs layer is formed. The case of irradiating light will be described with reference to FIG.

FIG. 1 is a plot of the laser power density dependence of the selectivity of reverse selective etching when the sample temperature is 110 ° C., the chlorine gas pressure is 600 mTorr, and the pulse frequency is 70 Hz. Within the measured laser power density range, the etching rate of InAlAs is InG
As the etching rate was higher than the aAs etching rate and the laser power density was lower, the inverse selectivity of InGaAs / InAlAs was increased. When the laser power density was 10 mJ / cm ² , the inverse selectivity was about 50. Laser power density 20mJ / cm
^In a region larger than ² , the reverse selectivity is less than 10, which is a practically insufficient reverse selectivity for use in high-precision semiconductor processing for manufacturing an electronic element for high-speed operation. Therefore, for high-precision semiconductor processing, it is necessary to set the laser power density to at least 20 mJ / cm ² or less.

As for InGaAs / InAlAs-based materials, the selection ratio of reverse selective etching tends to increase as the laser power density is reduced.
It cannot be inferred from the reported examples of the etching technique using pulsed laser light known from Japanese Unexamined Patent Publication (Kokai) No.-263383 and other well-known etching techniques using pulsed laser light. .

The wavelength of the excimer laser light is about 193 nm.
If not, for example, KrF excimer laser light 248 nm
Alternatively, XeCl excimer laser light of 351 nm may be used. However, when chlorine is used as an etching gas, a wavelength of about 19
The most effective method is to use an ArF excimer laser device that generates a 3 nm pulse laser beam as a light source. It's Chemical Physics Letters
As reported in Physics Letters), Vol.155, No.2, pp.162-167, for example, in a condensed system in which several atomic layers of chlorine are adsorbed on a semiconductor surface, absorption is observed at a wavelength around 193 nm. This is because the surface excitation reaction is promoted and the etching rate of the layer to be etched is increased as compared with the case of using light having a wavelength (for example, about 270 nm) greatly deviating from 193 nm because of having the maximum value.

In FIG. 1, the sample temperature (the back surface temperature of the sample when the surface irradiated with the laser beam is the front surface) is 110 ° C., but the inverse selectivity when the temperature is around room temperature (about 30 ° C.). FIG. 2 shows the laser power density dependency. As in the case of FIG. 1, the reverse selectivity exceeded 10 at a laser power density of 20 mJ / cm ² or less. That is, the laser power density is 20 mJ /
Practical reverse selective etching becomes possible at cm ² or less.
As described above, it was found that when the light power density was set to 20 mJ / cm ² or less, a large reverse selection ratio could be obtained even when the temperature was around room temperature.

FIG. 3 shows the laser power density dependence of the InAlAs / InGaAs selectivity when oxygen gas (O ₂ ) is mixed with chlorine gas. Here, the partial pressure of chlorine gas is 300 mTorr, and the partial pressure of oxygen gas is 500 mTorr.
And the sample temperature was 110 ° C. As shown in FIG. 3, when the laser power density is 40 mJ / cm ² or more, InAlAs and InGa
As etching rate becomes almost equal, InAlAs
And InGaAs can be etched at a constant rate. When the laser power density was 13 mJ / cm ² or less, the reverse selectivity exceeded 10, and when the laser power density was about 10 mJ / cm ² , the reverse selectivity was about 70.

The etching characteristics using pulsed light emitted from an excimer laser device have been described above. However, if the power density of the light is within the above-mentioned condition range, continuous light (for example, from an excimer lamp or a mercury lamp) is used. The same result can be obtained by using (emitted light).

As an etching gas, Cl _{2 is used.}
Only or a mixed gas of Cl ₂ and O ₂ was used.
₂ was a gas containing chlorine, or effects of the present invention the O ₂ as the gas containing oxygen is not changed.

The materials are InAlAs and InGaAs.
Not limited to the combination of In, Al and a semiconductor containing In and Al
The same reverse selective etching is possible as long as a combination of Si and Ga is used. Examples include combinations of InAlSb and InGaSb and combinations of InAlP and InGaP.

By the way, the following methods can be used as an etching method using InGaAs as an etching layer and InAlAs as an etching stop layer (Takazawa et al., The 43rd Spring Meeting of Applied Physics, 1996 (Heisei 8)). Proceedings of the Society, page 1228, lecture numbers 27p-M-14 and 27p-M-15).

HBr and F ₂ are each 60 mTorr.
Under an atmosphere of a gas mixed as r and 6 mTorr, a pulse frequency of 20 Hz was set so that the ArF excimer laser power density was about 6 mJ / cm ² on the sample surface.
And the sample temperature is 110 ° C. Under this condition, the forward selectivity is about 170, and it can be considered that the etching is practically stopped by the exposure of the surface of the InAlAs layer. By this etching technique, the InGaAs layer can be removed by etching, and the etching can be stopped at the InAlAs layer. In this forward selective etching, a large value of about 70 was obtained even when the gas pressure was reduced to 1/5 while maintaining the HBr / F ₂ gas partial pressure ratio at 10/1 (FIG. 4).

As described above, it is possible to perform etching with different material selectivities by changing the type and pressure of the etching gas, the power density of the laser beam, and the pulse frequency. In addition, since it takes almost no time to change the type and pressure of the etching gas, the power density of the laser beam, and the pulse frequency, a plurality of etchings having different material selectivities can be continuously performed. For example, a sample temperature of 110 ° C., HBr and F ₂ are each 6
Under an atmosphere of a gas mixture of 0 mTorr and 6 mTorr, a pulse frequency of 20H was set so that the ArF excimer laser light amount was about 6 mJ / cm ² on the sample surface.
Etching performed under irradiation conditions of z and sample temperature 11
0 ° C., 300 mTo each of chlorine gas and oxygen gas
rr and 500 mTorr, and a continuous selective etching and a reverse selective etching by continuously performing the etching performed under the condition of irradiating the ArF excimer laser light amount on the sample surface at about 10 mJ / cm ² at a pulse frequency of 70 Hz. Can be performed continuously.

Next, an etching apparatus for carrying out the etching method of the present invention will be described with reference to FIG.

The sample 101 to be etched is
2 is mounted on the sample holder 103. The vacuum chamber 102 is evacuated by a vacuum pump 104 until the degree of vacuum reaches at least 1 × 10 to ⁷ Torr or less.

An electromagnetic valve 105 and a variable leak valve 106 are installed in the vacuum chamber 102, and a gas (chlorine gas (Cl ₂ ) only, or chlorine gas and oxygen gas (O ₂ ) whose flow rate is controlled by a mass flow controller 107 therefrom. (Or a mixed gas of HBr gas and F2 gas) 108 is continuously introduced from a gas cylinder 109 into the vacuum chamber 102 (the above-described variable leak valve 1).
06, mass flow controller 107, gas cylinder 10
9 was represented by describing two each). The gas 108 may be introduced in a pulsed manner in synchronization with a pulsed laser beam oscillated from a laser device 111 described later.
At this time, by installing a molecular beam valve at the electromagnetic valve 105, the reactive gas 108 may be introduced in a pulsed and directional manner. Since the gas pressure near the sample 101 can be increased by using the molecular beam valve,
Since the etching time can be reduced by increasing the etching rate and the utilization efficiency of the reactive gas can be increased, there is an effect that the manufacturing cost can be reduced.

The pulse laser beam 110 is applied to a laser device 111
And irradiates the sample 101 in the vacuum chamber 102 through the window 113 through the optical system 112. Optical system 11
Reference numeral 2 includes an attenuator for adjusting the light amount, a homogenizer for uniformizing the light amount distribution, and a lens for adjusting the light after adjusting the light amount and equalizing the light amount distribution to a desired area (not shown). The optical system 112 has the effect of improving the in-plane uniformity of the pulse laser beam 110 applied to the sample 101, improving the in-plane uniformity of the etching amount of the sample 101, and improving the manufacturing yield. By attaching a light amount measuring device or a light amount distribution measuring device thereto, it is possible to manually or automatically adjust the light amount or the light amount distribution during etching.

The sample holder 103 is equipped with a temperature monitor 114 so that the temperature of the sample 101 can be sensed. The sensed temperature is fed back by a temperature control circuit (not shown), and the temperature of the sample 101 is adjusted by the heating / cooling device 115. Sample holder 1
03, temperature monitor 114, and heating / cooling device 115
Is mounted on a step moving stage 120, and can move a desired distance on a plane on which the sample 101 is mounted and a desired distance in a direction perpendicular to the plane on which the sample 101 is mounted.

The sample 101 is carried into and out of the vacuum tank 102 by a vacuum pump 116 via a sub-vacuum tank 117 which can reach the same degree of vacuum as the vacuum tank 102.

(Embodiment 1) An embodiment of an etching method and a method of manufacturing a semiconductor device according to the present invention will be described with reference to FIGS. FIGS. 6 to 10 show an H method using the etching method and the semiconductor device manufacturing method of the present invention.
FIG. 3 is a process chart for manufacturing an EMT.

The steps up to the step shown in FIG. 6 in the HEMT manufacturing step will be described below.

On one main surface of the semi-insulating InP substrate 1, MBE
(Molecular Beam Epitaxy) method, a non-doped InAlAs layer 2 serving as a buffer layer,
A non-doped InGaAs layer 3 serving as a channel layer, a non-doped InAlAs layer 4 (2 nm) serving as a spacer layer, and an n-type InAlAs layer 5 (12n
m), the non-doped InAlAs layer 6 (1
0 nm), n-type InGaAs layer 7 serving as an ohmic layer
(5 nm) and n-type InAlAs layer 8 (20 nm) and n-type InGaAs layer 9 (50 nm)
It was sequentially grown from the P substrate 1 side. Here, the In composition ratio x and y of each semiconductor layer were set to x = 0.52 and y = 0.53, respectively, so as to lattice match with the InP substrate.

Next, a groove 10 reaching at least the non-doped InAlAs layer 2 serving as a buffer layer from the surface was formed in a portion other than the HEMT fabrication region by using the usual photolithography technique and the etching method of the present invention (FIG. 6). . Here, as the etching condition, the chlorine gas partial pressure was set to 3
00 mTorr, oxygen gas partial pressure 500 mTorr, sample temperature 110 ° C., laser power density 40 m
J / cm ² and the pulse frequency were 70 Hz. Under these etching conditions, InGaAs and InAlAs are etched at substantially the same rate, so that a smooth etching side surface with almost no step near the junction interface between the InGaAs layer and the InAlAs layer on the side surface of the groove 10 can be obtained.

Next, an insulating film 11 was deposited, a portion for forming a source electrode and a drain electrode was opened by a usual photolithography technique and a usual dry etching method, and a source electrode 12 and a drain electrode 13 were formed. Here, the insulating film 11 is made of silicon oxide SiO ₂ , but may be made of another material, for example, silicon nitride SiNx, or a laminated structure of a plurality of insulating materials.

Next, the opening 1 corresponding to the gate length is formed by a usual photolithography technique and a usual dry etching method.
4 was formed on the insulating film 11. FIG. 7 is a cross-sectional view showing the state after the above steps. Although the photoresist film used in the above-described photolithography process is left on the insulating film 11 in FIG. 7, the photoresist film is omitted.

Then, as shown in FIGS. 8 to 10, the n-type InGaAs layers 7 and n serving as ohmic layers at the portions where gate electrodes are formed by using the etching method of the present invention.
Type InAlAs layer 8 and n-type InGaAs layer 9 are etched to form non-doped InAlAs layer 6 serving as a barrier layer.
Surface was exposed. As etching conditions, n-type In
When removing the GaAs layer 7 and the n-type InGaAs layer 9 (FIGS. 8 and 10 respectively), HBr and F
_In the case where the n-type InAlAs layer 8 is removed by irradiating an ArF excimer laser light amount on the sample surface at about 6 mJ / cm ² at a pulse frequency of 20 Hz in a gas atmosphere in which ₂ is set to 60 mTorr and 6 mTorr, respectively. (FIG. 9) shows that the partial pressure of chlorine gas is 300 mTo.
rr, the partial pressure of oxygen gas was set to 500 mTorr, the laser power density was set to 10 mJ / cm ² , and the pulse frequency was set to 70 Hz. The sample temperature was 110 ° C.

Next, a HEMT was completed by forming a gate electrode (not shown). The usual lift-off method was used for the electrode formation method.

The HEMT having the structure shown in this embodiment is a single layer of an n-type InGaAs layer as a semiconductor layer serving as an ohmic layer, as reported by Higuchi et al., 1994 IEICE Spring Conference C-565. In this structure, the source resistance is reduced as compared with a certain case, and the element performance can be improved. By using the etching technique of the present invention, the n-type InGaAs layer 7 (5 nm), the n-type InAlAs layer 8 (20 nm) and the n-type InGa
The accuracy of etching removal of the semiconductor laminated structure such as the As layer 9 (50 nm) was improved, the production yield of the element was improved, and the production cost was reduced.

In this embodiment, InP is used for the substrate denoted by reference numeral 1 shown in FIG. 6. However, by using the substrate as a GaAs substrate, the strain is relaxed by the non-doped InAlAs layer 2 serving as a buffer layer. Crystal growth can be performed so that three to nine semiconductor layers are lattice-matched to InP (Higuchi et al., IEICE Technical Report, ED94-117, 1995, pp.27-).
32). In this case, there is an effect of reducing raw material costs.

In this embodiment, the etching is performed under the above-described conditions. However, the conditions can be changed within the scope of the present invention without depending on the above-mentioned conditions by the design structure of the HEMT.

Embodiment 2 Another embodiment of a method of manufacturing a semiconductor device using the etching method of the present invention is shown in FIG.
This will be described with reference to FIG. 11 to 14 are process diagrams for manufacturing an HBT by the etching method of the present invention. In FIGS. 11 to 14, the photoresist and the insulating film are omitted.

The semi-insulating InP substrate 51 has MBE on one main surface.
Non-doped InAlAs layer 52, n + type InG
aAs layer 53, n-type InGaAs layer 54, p-type InG
aAs layer 55, n-type InAlAs layer 56, n-type InAl
The GaAs layer 57 and the n-type InGaAs layer 58 are made of semi-insulating I
It was sequentially grown from the nP substrate 51 side. Where p-type InG
The thickness of the aAs layer 55 was 20 nm. Next, a groove 59 reaching at least the non-doped InAlAs layer 52 was formed in a portion other than the HBT production region by using the ordinary photolithography technique and the etching technique of the present invention (FIG. 1).
1).

Here, as the etching conditions, a partial pressure of chlorine gas was set to 300 mTorr, and a partial pressure of oxygen gas was set to 500 mTo.
rr, the sample temperature was 110 ° C., the laser power density was 40 mJ / cm ² , and the pulse frequency was 70 Hz. Under these etching conditions, InGaAs and InAlAs are etched at substantially the same speed, so that a smooth etched side surface having almost no step near the junction interface between the InGaAs layer and the InAlAs layer on the side surface of the groove 59 can be obtained.

Next, the n + -type InGaAs layer 5 is formed by using the usual photolithography technique and the etching technique of the present invention.
3 was formed. Here, as etching conditions, a partial pressure of chlorine gas was set to 300 mTorr, a partial pressure of oxygen gas was set to 500 mTorr, a sample temperature was set to 110 ° C., a laser power density was 40 mJ / cm ² , and a pulse frequency was 70 Hz.
And As described above, a smooth etching side surface is obtained. Next, a collector electrode 60 was formed by a normal lift-off method (FIG. 12).

Next, the n-type InGaAs layer 5 is formed by using the ordinary photolithography technique and the etching technique of the present invention.
8. The n-type InAlGaAs layer 57 and the n-type InAlAs layer 56 were removed by etching (FIG. 13). n-type InGaAs
s layer 58, n-type InAlGaAs layer 57, n-type InAl
The As layer 56 is an emitter layer in the HBT of this embodiment. Here, as an etching condition, a chlorine gas partial pressure is set to 30.
0 mTorr, the partial pressure of oxygen gas is 500 mTorr,
The sample temperature was 110 ° C. and the pulse frequency was 70 Hz. The laser power density is initially 40 mJ / cm ² and n
10 mJ / after removing the type InAlGaAs layer 57
It switched to cm ^2. Laser power density 10mJ / cm ²
Since the reverse selective etching can be performed as described above, after the n-type InAlAs layer 56 is removed, the n-type I
The etching stops practically near the interface between the nAlAs layer 56 and the p-type InGaAs layer 55. The switching of the laser power density was performed by measuring the etching time. Here, the same reverse selective etching can be performed even when the laser power density is switched to 10 mJ / cm ² and the introduction of oxygen gas is stopped and etching is performed only with chlorine gas.

Next, a base electrode 61 is formed by a normal lift-off method, and then an emitter electrode 62 is formed by a normal lift-off method to complete the HBT (FIG. 1).
4).

Conventionally, the thickness of the p-type InGaAs layer 55 is 3
Although it was difficult to reduce the thickness to less than 0 nm, in this embodiment, since the thickness of the p-type InGaAs layer 55 was reduced to 20 nm, the base transit time of carriers was reduced, and higher-speed operation was possible than in the past. The device was able to be manufactured. Conventionally, it has been difficult to reduce the thickness of the p-type InGaAs layer 55 to less than 30 nm because an etching margin is required because a wet etching method with low selectivity is used for etching. By using the etching method of the present invention, p-type InGa
It has become possible for the first time to make the As layer 55 thinner. Although the thickness of the p-type InGaAs layer 55 is set to 20 nm in this embodiment, it goes without saying that the thickness can be further reduced.

By using the etching method of the present invention, the etching can be accurately stopped near the interface between the n-type InAlAs layer 56 and the p-type InGaAs layer 55, and the HBT production yield can be improved and the cost can be reduced.

As described in the first embodiment, even if the InP substrate denoted by reference numeral 51 is a GaAs substrate, crystal growth is performed so as to lattice-match the semiconductor layers denoted by reference numerals 53 to 58 with InP by relaxing strain. You can also. In this case, there is an effect of reducing raw material costs.

In this embodiment, the etching is performed under the above-described conditions. However, the conditions can be changed without departing from the spirit of the present invention without depending on the above-mentioned conditions by the design structure of the HBT.

[0050]

According to the present invention, the performance of the semiconductor device can be improved, and at the same time, the yield in the manufacture of the semiconductor device can be improved and the manufacturing cost of the semiconductor device can be reduced.

[Brief description of the drawings]

FIG. 1 is a measurement diagram of the etching selectivity of InAlAs and InGaAs by laser irradiation with Cl ₂ gas according to the method of the present invention.

FIG. 2 is a diagram showing a measurement of the etching selectivity of InAlAs and InGaAs by laser irradiation with Cl ₂ gas according to the method of the present invention.

FIG. 3 is a diagram showing a measurement of the etching selectivity of InAlAs and InGaAs by laser irradiation with Cl ₂ + O ₂ gas according to the method of the present invention.

FIG. 4 is a measurement diagram showing an etching selectivity between InGaAs and InAlAs when a partial pressure ratio between HBr gas and F ₂ gas is set to 10/1.

FIG. 5 is a block diagram showing a schematic configuration of an etching apparatus for performing the etching method of the present invention.

FIG. 6 is a sectional view showing a manufacturing process of the semiconductor device according to one embodiment of the present invention;

FIG. 7 is a sectional view showing the manufacturing process of the semiconductor device according to one embodiment of the present invention;

FIG. 8 is a sectional view showing a manufacturing process of the semiconductor device according to one embodiment of the present invention.

FIG. 9 is a sectional view showing a manufacturing process of the semiconductor device according to one embodiment of the present invention;

FIG. 10 is a sectional view showing the manufacturing process of the semiconductor device according to one embodiment of the present invention;

FIG. 11 is a sectional view showing a manufacturing process of the semiconductor device according to one embodiment of the present invention;

FIG. 12 is a sectional view showing a manufacturing process of the semiconductor device according to one embodiment of the present invention;

FIG. 13 is a sectional view showing a manufacturing step of the semiconductor device according to one embodiment of the present invention;

FIG. 14 is a sectional view showing a manufacturing process of the semiconductor device according to one embodiment of the present invention;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semi-insulating InP board, 2 ... Non-doped InAlAs layer used as a buffer layer, 3 ... Non-doped InGaAs layer used as a channel layer, 4 ... Non-doped In used as a spacer layer
AlAs layer, 5 n-type InAlA serving as carrier supply layer
s layer, 6... a non-doped InAlAs layer serving as a barrier layer,
7 n-type InGaAs to be an ohmic layer, 8 n-type InAlAs to be an ohmic layer, 9 n-type InGaAs to be an ohmic layer, 10 grooves.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication H01L 29/778 21/338 29/812

Claims (10)

[Claims] 1. A semiconductor layer containing In and Al, and In and G
By irradiating a sample on which a semiconductor laminated film having a laminated structure of a semiconductor layer including a is formed on the surface thereof in an atmosphere of a gas containing chlorine, the semiconductor layer containing In and Al is covered. An etching method, wherein an etching layer is formed, the semiconductor layer containing In and Ga becomes an etching stop layer, and the power density of the light is 20 mJ / cm ² or less. 2. The etching method according to claim 1, wherein the gas containing chlorine is Cl ₂ . 3. The laser light having a wavelength of about 193 nm emitted from an ArF excimer laser.
Or the etching method according to 2. 4. A semiconductor layer containing In and Al, and In and G
A sample in which a semiconductor laminated film having a laminated structure of a semiconductor layer containing a is formed on a surface is irradiated with light under a mixed gas atmosphere of a first gas containing chlorine and a second gas containing oxygen. Thereby, the semiconductor layer containing In and Al becomes a layer to be etched, the semiconductor layer containing In and Ga becomes an etching stop layer, and the power density of the light is 13 mJ /.
etching wherein the cm ^{2 or} less. 5. The etching method according to claim 4, wherein said first gas is Cl ₂ . 6. The etching method according to claim 4, wherein said second gas is O ₂ . 7. The etching method according to claim 4, wherein the light is a laser pulse light having a wavelength of about 193 nm emitted from an ArF excimer laser. 8. A semiconductor layer containing the In and Ga are In _x Ga _1-x As the In composition ratio x is less than 1 at greater than 0, the semiconductor layer is an In composition ratio y including the In and Al Is 0
The etching method according to claim 1, 2, 3, 4, 5, 6, or 7, wherein In _y Al _1-y As is larger and less than ₁ . 9. HEMT (High Electron)
A semiconductor layer containing In and Ga is etched by irradiating light to the etching method according to claim 1, 2, 3, 4, 5, 6, 7, or 8 in a gate recess forming step of Mobility Transistor. A method of manufacturing a semiconductor device, wherein an etching method in which a semiconductor layer containing In and Al is used as an etching stop layer is alternately used. 10. HBT (Hetero Bipolar)
A method for manufacturing a semiconductor device, wherein the etching method according to claim 1, 2, 3, 4, 5, 6, 7, or 8 is used in an emitter layer removing step of a transistor.