JPH07335620A - Selective dry-etching method for ii-vi group compound semiconductor - Google Patents

Abstract

PURPOSE:To obtain a selective dry-etching method for a II-VI group compound semiconductor by a method wherein noble gas of specific volume ratio is introduced into a treatment chamber wherein the material to be etched is arranged, and the material to be etched is dry-etched by the impulse of noble gas ions against the material to be etched. CONSTITUTION:When a cathode coupling system, in which the material to be etched 1 is arranged on the side of a cathode 4 where high frequency power is applied from a high frequency power source 3 through a matching circuit 8, is adopted, the opposing electrode 5 with the cathode 4 is used as an earthing electrode. A treatment chamber 2, where the material to be etched 1 will be arranged, is retained in a high vacuum state by evacuating from an exhaust hole 6 using an evacuation means, and gas, having 80% or more of noble gas, is introduced into the treatment chamber 2 from a gas feeding hole 7. One or more kinds selected from He and Kr, for example, are used as the above- mentioned noble gas. As a result, the control of the depth of etching, accurate processing on II-VI group, in other words, can be conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for selectively dry etching II-VI group compound semiconductors, such as III-V group compound semiconductors, for selectively etching II-VI group compound semiconductors.

[0002]

2. Description of the Related Art As a semiconductor light emitting device for emitting blue or green light having a relatively short wavelength, such as a laser diode or a light emitting diode, a semiconductor light emitting device made of a II-VI group compound semiconductor has been attracting attention.

[0003] cladding semiconductor light emitting device according to the II-VI compound semiconductor is generally of or GaAs substrate, for example of the group III-V _{Ga z In 1-z P (} 0 ≦ z ≦ 1) constituting the semiconductor light emitting elements on a substrate II, such as layers and active layers
The group VI semiconductor layer is formed by epitaxy.

In this case, II- formed on a III-V substrate in a monolithic integrated circuit by combining a plurality of light emitting elements or by combining with other elements.
It is required to selectively etch away the II-VI group compound semiconductor while leaving the III-V group substrate for the VI group compound semiconductor.

Further, recently, red, green and blue semiconductor light emitting elements are laminated on a common substrate, and research and development of a color light emitting element for performing full color light emission by these light emitting elements are actively conducted. ing. In this case, at least a blue light emitting element is a II-VI group light emitting element, and at least a red light emitting element is a III-V light emitting element.
The light emitting element is a group.

Also in this case, because of the necessity of forming electrodes for leading terminals from the light emitting elements of each color, for example, the II-VI group semiconductor layer located on the upper layer side is, for example, III-V.
It is necessary to selectively etch the group semiconductor layer or the substrate while leaving it.

As the etching method, many etching methods such as plasma etching such as RIE (Reactive Ion Etching) are known. Since this kind of etching is anisotropic etching, it is suitable for fine processing. However, with respect to III-V group compound semiconductors, I
No proposal has been made yet for a method capable of selectively dry etching only a group I-VI compound semiconductor.

[0008]

SUMMARY OF THE INVENTION The present invention is a III-V
A method for selectively dry-etching a II-VI group compound semiconductor capable of selectively etching a II-VI group compound semiconductor with respect to a group compound semiconductor.

[0009]

In the first method of the present invention, a II-VI group compound to be etched is shown in FIG. 1, which is a schematic configuration diagram of an example of an etching apparatus for performing the etching according to the present invention. 80% (volume ratio) in the processing chamber 2 in which the etching target 1 having a semiconductor is arranged.
The II-VI group compound semiconductor is selectively etched mainly by dry etching by introducing the gas of the above rare gas and impacting the object to be etched 1 with the rare gas ions.

A second method of the present invention is the method of the above-mentioned present invention, wherein the II-VI group compound semiconductor is III-V.
Etching is selectively performed on the group compound semiconductor.

In a third method of the present invention, in each of the above-mentioned methods of the present invention, the rare gas is at least one of Ar, He, and Kr.

[0012] A fourth method of the present invention, in each of the inventive method described above, the object of the etching Group II-VI compound _{semiconductor, Zn 1-xy Mg x Cd} y S a Te b Se
_1-ab (0 ≦ x <1, 0 ≦ y <1, 0 ≦ a <1, 0 ≦ b
<1).

In the fifth method of the present invention, the III-V group compound semiconductor in each of the above-mentioned methods of the present invention is
GaAs or Ga _z In _1-z P (0 ≦ z ≦ 1).

[0014]

According to the method of the present invention described above, only the II-VI group compound semiconductor can be selectively etched with respect to the III-V group compound semiconductor. This is because, in the dry etching, the introduced gas is set to 80% or more of the rare gas, so that the chemically reactive etching hardly occurs and the physical etching mainly occurs by the impact of the ions of the rare gas. And in this case II-V
Since the bond between the atoms of the group I compound semiconductor is weaker than the similar bonding force in the group III-V compound semiconductor,
The etching rate for II-VI group compound semiconductors is higher than the etching rate for III-V group compound semiconductors, and it is considered that the II-VI group compound semiconductors are selectively etched for this reason. By the way, the Debye temperature, which is a measure of the strength of the crystal, is the II-VI group Zn.
Se and III-V group GaAs are 271 and 376, respectively, with III-V group GaAs having higher values.

As described above, according to the method of the present invention, III
Since the II-VI group compound semiconductor can be selectively etched with respect to the -V group compound semiconductor, as described above, a monolithic integrated circuit having a II-VI group compound semiconductor light emitting element, a color light emitting element, or the like can be manufactured. It can be done easily and reliably.

[0016]

EXAMPLES Examples of the method of the present invention will be described. The method of the present invention can be carried out by an etching apparatus known as a parallel plate type etching apparatus shown in FIG. 1, for example. That is, this etching apparatus adopts a cathode coupling method in which the object to be etched is arranged on the side of the cathode 4 to which the high frequency power from the high frequency power source 3 is applied through the matching circuit 8, for example, and the counter electrode 5 with the cathode 4 is used. However, the etching apparatus is not limited to this example, and various configurations can be adopted, such as an anode coupling method.

The inside of the processing chamber 2 in which the object to be etched is placed is evacuated from the exhaust port 6 by an exhaust means (not shown) to maintain a high degree of vacuum, and the inside of the processing chamber 2 is supplied from the gas supply port 7. A gas having 80% or more as a rare gas is introduced.

As the rare gas, for example, at least one of Ar, He and Kr can be used.

The II-VI group compound semiconductor to be etched is, for example, Zn _1-xy Mg _x Cd _y S _a T
e _b Se _1-ab (0 ≦ x <1, 0 ≦ y <1, 0 ≦ a <
1, 0 ≦ b <1), avoiding etching III
-V compound semiconductor, for example GaAs or Ga _z I
Let n _1-z P (0 ≦ z ≦ 1).

As shown in FIG. 2A, III-V group GaA
With respect to the object to be etched 1 obtained by epitaxying the semiconductor layer 22 made of II-VI ZnSe on the s substrate 21, only the ZnSe semiconductor layer 22 is selectively formed into a desired pattern while leaving the GaAs substrate 21. The case of etching by the method will be described with reference to examples.

In this case, as shown in FIG. 2A, an etching mask 23 having an opening 23W is formed on the semiconductor layer 22 of the object to be etched 1 by etching, for example, by applying a photoresist, pattern exposure, and development. .

Then, the object to be etched 1 is placed on the cathode 4 of the etching apparatus described with reference to FIG. 1 to perform etching according to the present invention. This etching was performed under the conditions given in the following examples.

Example 1 Introduced gas Ar pressure 25 mTorr High-frequency output 100 W According to the method of Example 1, the etching rate is ZnSe 8 nm / min GaAs 0.7 nm / min, which is high for ZnSe and GaAs. Shows sex.

Therefore, under the conditions of the first embodiment, as shown in FIG.
When the object to be etched 1 shown by A is etched, only the portion of the ZnSe semiconductor layer 22 exposed to the outside through the opening 23W is etched as shown in FIG. 2B. Then, in this case, the etching of the semiconductor layer 22 is performed over its entire thickness, and the GaAs substrate 2
When 1 is exposed to the outside, the etching rate thereof rapidly decreases. Therefore, if etching is stopped at this point, only the semiconductor layer 22 can be selectively etched. In this case, when the GaAs substrate 21 is exposed to the outside,
Since the etching rate sharply decreases, the detection at this point and the control of the etching stop can be easily and surely performed.

In the first embodiment described above, Ar is used as the introduction gas.
However, He gas can also be used as the introduction gas as in Example 2 described below.

Example 2 Introduced gas He pressure 75 mTorr High frequency output 100 W According to the method of Example 2, the etching rate was ZnSe 7 nm / min GaAs 0.9 nm / min, and in this case also ZnSe and GaAs Shows high selectivity for.

In each of the above examples, the II-VI group compound semiconductor is ZnSe and the III-V group compound semiconductor is G.
Although shown as aAs, similar selectivity was shown for other II-VI group compound semiconductors and III-V groups.

For example, the etching rates for the II-VI group and III-V group compound semiconductors when the same etching as in Example 2 is performed will be illustrated.

II-VI group ZnSe 7 nm / min ZnSSe 6 nm / min ZnMgSSe 7 nm / min ZnTe 8 nm / min III-V group GaAs 0.9 nm / min GaInP 1.5 nm / min

Next, for comparison, an example of etching when a rare gas as an introduced gas is less than 80% is shown as Comparative Example 1.
As an example. In this case as well, etching was performed using the etching apparatus described in FIG.

Comparative Example 1 Introduced gas and its flow rate ratio SiCl ₄ : He = 1
0: 8.6 (46% of rare gas) Pressure 25 mTorr High-frequency output 100 W According to the method of Comparative Example 1, the etching rate is ZnSe 30 nm / min GaAs 400 nm / min, and in this case II-VI. Group compound semiconductor Zn
Compared to Se, it showed higher etching properties for III-V group GaAs.

Etching rates R of ZnSe and GaAs obtained in Comparative Example 1 and when the introduced gas was He alone (He 100%) under the same conditions as in Comparative Example 1.
Ratio of _ZnSe and R _GaAs , that is, selection ratio R (R = R _ZnSe / R
This selection ratio R and the rare gas H in the introduced gas based on _GaAs )
Looking at the relationship with the ratio of e, the relationship shown in FIG. 3 is obtained. As a result, the ratio of noble gas in the introduced gas is increased to 8
It can be seen that the selection ratio R> 0 can be achieved when the content is 0% or more.

According to the method of the present invention, it is possible to perform dry etching having a high etching selectivity of the II-VI group compound semiconductor with respect to the III-V group compound semiconductor, but the etching rate itself is relatively high. Therefore, for example, when etching a comparatively thick II-VI group compound semiconductor, etching for a long time is required, which causes a problem of workability and the etching mask 23. The issue of corruption will need to be considered. In this case, in the initial stage of etching the II-VI group compound semiconductor layer, normal RIE, that is, etching in which a reactive gas is mixed in the introduced gas as in Comparative Example 1,
A method of selectively etching only the II-VI compound semiconductor by switching to the etching of the method of the present invention at a position near the interface with the III-V compound semiconductor can be adopted.

In the method of the present invention, when the semiconductor layer 21 made of a II-VI group compound semiconductor is etched to a predetermined depth, the method of the present invention is used.
By utilizing the etching selectivity with respect to the semiconductors of the group III and the group III-V, it is possible to reliably perform etching to a predetermined depth. That is, in this case, the III-V compound semiconductor layer is used as a stopper for etching.

An example of this case will be described with reference to FIG. In this case, as shown in FIG. 4A, the first semiconductor layer 22 made of, for example, ZnSe of a II-VI group compound semiconductor having a required thickness, for example, made by MBE (Molecular Beam Epitaxy).
For example, MOCVD (Metal Organic Chemical V
The stopper layer 24 made of III-V compound semiconductor, for example, GaAs, is formed to a desired thickness d _S by apor deposition.
With, for example, epitaxy. Then, a second semiconductor layer 22B made of, for example, ZnSe, which is the same as the II-VI group compound semiconductor and has a required thickness d, is formed on top of this, for example, by MBE.
Epitaxy by.

In this case, the sum of the thickness d _S of each stopper layer 24 and the thickness d of the second semiconductor layer 22B becomes the target etching depth D (that is, D = d + d _S ). To be selected.

Then, on the second semiconductor layer 22B, an etching mask 23 having an opening 23W at a portion to be etched is formed by, for example, photoresist coating, pattern exposure, and development processing.

As shown in FIG. 4B, the etching mask 2
Layer 22B exposed to the outside through the opening 23W of No. 3
Is etched, for example, according to Example 1 or 2 above. At this time, the etching progresses and III-V
When the stopper layer 24 of the group compound semiconductor is exposed, the etching rate thereof is drastically reduced, so that the etching is stopped at this point. As described above, the stop of the etching sharply decreases the etching rate, and therefore the detection and the stop can be easily performed.

Next, as shown in FIG. 4C, the stopper layer 24 exposed to the outside by the etching of the first semiconductor layer 22B is etched by, for example, the method of Comparative Example 1 described above. By doing so, only the stopper layer 24 can be selectively etched, and the predetermined depth D (D = d + d _S ) can be obtained by the etching of the second semiconductor layer 22B and the etching of the stopper layer 24 described above. Pattern etching can be performed.

As described above, according to the method of the present invention, I
The II-VI group compound semiconductor can be selectively etched with respect to the II-V group, and since this etching is ionization of a rare gas, that is, plasma etching, the etching is excellent in anisotropy.

The selective dry etching method according to the method of the present invention has a structure in which, for example, three primary color red, green and blue light emitting elements R, G and B are laminated, and these are individually driven to emit light. This is applied when manufacturing a semiconductor color light emitting element that emits full color light by combining these lights, and the electrode lead-out portion can be formed easily and reliably.

First, a schematic structure of this semiconductor color light emitting device will be described with reference to FIG. In this example, on the GaAs substrate 31, red, green, and blue, for example, each semiconductor light emission by a light emitting diode or a semiconductor laser, which includes a group III-V compound semiconductor light emitting element and a group II-VI compound semiconductor light emitting element lattice-matched to GaAs. The elements R, G and B are laminated to form a semiconductor color light emitting element 50.

Here, the red semiconductor light emitting element R having a relatively long wavelength and, in some cases, the green semiconductor light emitting element G are I
II-V group structure, and at least a blue semiconductor light emitting device B having a short wavelength, and in some cases, a green semiconductor light emitting device G is I
I-VI group system configuration.

The group III-V compound semiconductor light emitting device is
Desirably composed of 1GaInP-based compound semiconductor
The II-VI group compound semiconductor light emitting device is_1-xy
Mg _xCd_yS_aTe_bSe_1-ab(0 ≦ x <1, 0 ≦
The configuration is such that y <1, 0 ≦ a <1, 0 ≦ b <1).

Contact layers 52, 53 and 54 are formed between the respective semiconductor light emitting elements R, G and B and on the upper surface of the uppermost semiconductor light emitting element (light emitting element B in the example of FIG. 5).

Then, a first electrode 41 made of, for example, In is formed on the back surface of the GaAs substrate 31 by ohmic deposition.
Above each semiconductor light emitting device B, G and R (GaAs
The contact layers 52, 53, and 54 (on the side opposite to the substrate 31) have second, third, and fourth electrodes 42, 4 respectively.
Ohmic deposits 3 and 44.

FIG. 6 shows the equivalent of this semiconductor color light emitting device.
Shows the circuit, each terminal T₁~ T _FourAre the first
-The terminal of the 4th electrodes 41-44 is shown. With this configuration
If terminal T₁And T₂ Between terminals T₂ And T₃while,
Terminal T₃And T_FourSupply required drive voltage between each
To control each light emitting element R, G, B independently
it can. Therefore, these elements R, G, B are combined.
By making them emit light, they are synthesized by combining these lights.
It is possible to emit a red light.

In this case, the semiconductor light emitting devices R, G and
The light emission of B is indicated by arrow A in FIG. _R, A_GAnd A_B
As shown in FIG.
A horizontal configuration can also be used in which light is emitted from the end face of the conductor layer.
However, a vertical type, that is, an arrow B crossing the surface of the semiconductor layer_R,
B_GAnd B_BSo-called surface-emitting type structure that emits light in one direction
Can also be

In the case of the surface emission type structure, the red, green and blue semiconductor light emitting elements R, G and B are stacked in the order of red, green and blue, and color light emission is taken out from the blue semiconductor light emitting element B side.

The semiconductor color light emitting device 50 is
The common GaAs substrate 31 may be arranged one-dimensionally, that is, in one column, or may be two-dimensionally arranged, that is, in a row and column direction in which a plurality of each cross each other.

As shown in FIG. 7, the semiconductor color light emitting device 50 has a red, green, and blue semiconductor light emitting devices R, G, and B finally having a double hetero structure on a GaAs substrate 31, respectively. A light emitting element constituting substrate 61 on which green, blue and blue light emitting element constituting portions 61R, 61G and 61B are formed is prepared.

The red light emitting element component 61R has, for example, a thickness of
0.5 μm n-type (Al_0.6Ga _0.4)_0.5In_0.5
The first clad layer 71R made of P and having a thickness of 0.
3 μm undoped or low concentration n-type or p-type
Of (Al_0.2Ga_0.8)_0.5In_0.5Active layer made of P
72R and, for example, a 0.5 μm thick p-type (Al_0.6G
a_0.4)_0.5In_0.5Second cladding layer 73 made of P
R and R are sequentially epitaxially formed.

Then, a contact layer 52 for contacting the above-mentioned second electrode 42 made of p-type GaAs having a thickness of 0.2 μm, for example, is epitaxy on the constituent portion 61R, and a green light emitting element structure is formed thereon. Epitaxy part 61G. The constituent portion 61G is, for example, a first portion made of p-type (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P having a thickness of 0.5 μm.
Of the clad layer 71G and an undoped or low-concentration n-type or p-type (Al _0.6 G
a _0.4 ) _0.5 In _0.5 P active layer 72G and, for example, 0.5 μm thick n-type (Al _0.7 Ga _0.3 ) _0.5 I
A second cladding layer 73G made of n _0.5 P is sequentially formed by epitaxy.

Further, the third electrode 4 made of n-type GaAs having a thickness of 0.5 μm, for example, is formed on the constituent portion 61G.
The contact layer 53 which contacts 3 is epitaxyed, and the blue light emitting element constituting portion 61B is epitaxy thereon. This constituent portion 61B includes, for example, a first cladding layer 71B made of n-type Zn (S _0.07 Se _0.93 ) having a thickness of 0.5 μm, a barrier layer of ZnSe having a thickness of 6 nm, and a (Zn _0.9 Cd having a thickness of 4 nm). _0.1 ) an active layer 72B having a TQW (triple quantum well) structure formed by repeatedly stacking with a Se quantum well layer, and a p-type layer Zn (S
The second cladding layer 73B made of _0.07 Se _0.93 ), the cap layer 74 made of a superlattice structure of p-type ZnTe and ZnSe, and the contact layer 54 made of ZnTe for contacting the third electrode 43 are sequentially epitaxially grown. To form.

In this way, the red light emitting element forming portion 61R-contact layer 52-green light emitting element forming portion 61G-contact layer 53-blue light emitting element forming portion 61B-contact layer 54 are formed on the GaAs substrate 1. Further, the light emitting element forming substrate 61 is formed.

Then, in order to contact the third electrode 43 shown in FIG. 5 with the light emitting element forming substrate 61 having this structure, a part of the contact layer 53 is exposed to the outside, and a blue light emitting element forming portion 61B. However, the contact layer 53 can be surely exposed by applying the selective etching of the method of the present invention to this etching.

That is, in this case, an etching mask (not shown) is formed on a portion of the blue light emitting element forming portion 61B to be left as the blue light emitting element B in FIG. 5, and the etching according to the first or second embodiment described above is performed, for example. To do. By doing so, the etching of the II-VI group compound semiconductor other than the constituent portion of the blue light emitting element B proceeds, and when the contact layer 53 is exposed to the outside, the etching rate thereof rapidly decreases. Stop etching.

Even in the etching of the blue light emitting element forming portion 61B, as described above, in the initial stage of etching, the rare gas is less than 80%, and the etching is performed to a certain depth by, for example, RIE. It is also possible to perform etching with the rare gas at 80% or more by the method of the present invention.

After that, in order to contact the second electrode 42 shown in FIG. 5, a part of the green light emitting element constituting portion 61G exposing a part of the contact layer 52 to the outside is etched over its entire thickness. Work is done. In this etching, the formation portions of the blue and green light emitting elements B and G shown in FIG. 5 are covered with an etching mask (not shown), and the contact layer 53 exposed to the outside is mixed by, for example, ammonia and hydrogen peroxide solution. It is removed by chemical etching with an etching solution. Then, the AlGaInP-based green light emitting element constituent portion 61G thereunder is subjected to chemical etching using an etching solution of, for example, an aqueous solution of hydrochloric acid or a mixed solution of hydrochloric acid and hydrogen peroxide solution.

In this case, this etching is AlGaIn.
The light emitting element forming portion 61G made of P is satisfactorily etched, but the etching rate of GaAs is extremely slow. Therefore, the etching apparently stops when the contact layer 52 made of GaAs is exposed to the outside. Therefore, if etching is stopped at this point, the contact of the second electrode 42 shown in FIG. 5 can be exposed to the outside.

Since a part of the contact layers 52, 53 and 54 are exposed to the outside as described above, the second, third and fourth electrodes 42, 43 and 44 are respectively formed on the contact layers 52, 53 and 54. Is ohmic-contacted, and the back surface of 31 is ohmic-contacted with the first electrode 41.

As mentioned above, according to the present invention, II-
Use of III-V group compound semiconductors as stoppers in the manufacture of various compound semiconductor devices by combination of VI group compound semiconductors and III-V group compound semiconductors, or in II-VI group etching as described in FIG. Therefore, the II-VI group compound semiconductor is etched to a required depth, and the etching can be surely performed by using it for the processing.

[0063]

As described above, according to the method of the present invention, I
Since only the II-VI group compound semiconductor can be selectively etched with respect to the II-V group compound semiconductor,
The etching of the II-VI group compound semiconductor, the regulation of the depth of this etching, and the accurate processing for the II-VI group are possible, and the desired monolithic integration having the II-VI group compound semiconductor light emitting device as described above, for example. It is possible to easily and surely manufacture a circuit, a color light emitting element and the like.

[Brief description of drawings]

FIG. 1 is a block diagram of an example of an etching apparatus for carrying out the method of the present invention.

FIG. 2 is a process chart of an application example of the method of the present invention. A is a sectional view in the one step. B is a sectional view in the one step.

FIG. 3 is a proportion of rare gas He in an introduced gas at the time of etching used for explaining the method of the present invention and II-VI group and I group.
It is a figure which shows the relationship with the selection ratio of a II-V group compound semiconductor.

FIG. 4 is a process chart of another application example of the method of the present invention. A is a sectional view in the one step. B is a sectional view in the one step. C is a sectional view in the one step.

FIG. 5 is a perspective view of an element of a semiconductor color element obtained by applying the method of the present invention.

FIG. 6 is an equivalent circuit diagram of a semiconductor color light emitting device.

FIG. 7 is a schematic cross-sectional view of a light emitting element constituent substrate of a semiconductor light emitting color element obtained by applying the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Etching object 2 Processing chamber 3 High frequency power supply 4 Cathode 5 Counter electrode 6 Exhaust port 7 Gas supply port 21 Substrate 22 Semiconductor layer 23 Etching mask

Claims (5)

[Claims] 1. A gas containing 80% or more of a rare gas is introduced into a processing chamber in which an object to be etched having a II-VI group compound semiconductor to be etched is disposed, and the object to be etched mainly contains the rare gas ions. A method for selective dry etching of a compound semiconductor, wherein the II-VI group compound semiconductor is selectively etched by dry etching by impact with. 2. The II-VI group compound semiconductor according to II
The selective dry etching method for a II-VI group compound semiconductor according to claim 1, wherein the group-IV group compound semiconductor is selectively etched. 3. The rare gas is Ar, He, or Kr.
3. The method for selective dry etching of II-VI group compound semiconductors according to claim 1, wherein at least one of the above is used. 4. The II-VI compound semiconductor is Zn
_{1-xy Mg x Cd y S} a Te b Se 1-ab (0 ≦ x <
II-VI according to claim 1, 2 or 3, wherein 1, 0 ≤ y <1, 0 ≤ a <1, 0 ≤ b <1).
Method for selective dry etching of group III compound semiconductors. 5. The group III-V compound semiconductor is Ga.
As or _{Ga z In 1- z P (0} ≦ z ≦ 1) , characterized in that it is according to claim 1, 2, 3 or 4 II-
Group VI compound semiconductor selective dry etching method.