JPH10242582A - Processing method of iii-v compound semiconductor and manufacture of iii-v compound semiconductor laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a vertical end surface of a III-V compound semiconductor even when it contains an Al composition. SOLUTION: On an initial structure 20 of a III-V compound semiconductor with a principal surface, matching an etching mask layer 30 in its plan view with the planar shape of a semiconductor laser 40 of the structure to be etched finally, the etching mask layer 30 having its edge orthogonal to [0-1-1] direction along the place to form there a vertical end surface 43 is formed to perform thereafter the vapor-phase etching of the initial structure 20 by using an alkyl chloride gas as an etching gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a group III-V compound semiconductor, and more particularly to an improvement for forming an end face as perpendicular as possible to a main surface of the group III-V compound semiconductor.

[0002]

2. Description of the Related Art As a starting member for manufacturing various microelectronic devices handled in a so-called integrated circuit category, instead of a classic silicon-based semiconductor, a GaAs-based or AlGa-based semiconductor has recently been used.
As-type, or III- represented by InP, AlGaInP-type, etc.
The use of Group V compound semiconductors is also increasing due to various physical advantages. Also, some of the devices to be fabricated require that, as a structural requirement, be as perpendicular as possible, and preferably truly perpendicular, to the major surfaces of such III-V compound semiconductor materials, typically provided as substrates or wafers. It is sometimes necessary to have a pair of steep mirror surfaces facing each other at both ends of a stripe-shaped laser active layer in order to satisfy a Fabry-Perot cavity structure essential for laser oscillation. Lasers are a typical example.

[0003] On the other hand, not only the III-V compound semiconductor but also a semiconductor processing method widely and generally, the purpose of the processing method for forming such a steep end face is as follows. , Conventional method 1: Cleavage method for physically cutting a semiconductor substrate or wafer, Conventional method 2: Wet etching method for etching in a liquid phase environment, Conventional method 3: Drying using an etching gas such as Cl ₂ or Ar Etching method, Conventional method 4: Gas phase etching method using Cl ₂ or HCL etching gas.

[0004]

SUMMARY OF THE INVENTION The above-mentioned conventional methods 1-4
Are not well-known in the art, since they are all very well known in this field, but as mentioned above, as described above, the method of processing III-V compound semiconductors, in particular III-V
There is no satisfactory method for cutting an end face perpendicular to the main surface of a group III compound semiconductor substrate or wafer to a sufficiently satisfactory degree. This method tends to have an adverse effect on the characteristics of the electronic device to be manufactured.

That is, the conventional method 1 (cleavage method) is not at all suitable for increasing the integration density of electronic devices, which is one of the basic requirements in recent years. Beyond relying on physical severing, integration has significant limitations. The breaking line must always be straight and no other electronic devices should be located on the breaking line. First, it is not possible to cut at too fine a pitch. In addition, a large number of recombination levels are likely to be present on the cleavage plane. Therefore, for example, as described above, when this technique is applied to the formation of the laser resonator mirror surface of a semiconductor laser, the non-emission current at the end face increases. Becomes a problem,
Positive feedback phenomenon toward element destruction called COD (Catastrophic Optical Damage) may occur, such as increase in end face temperature due to current increase, and further increase in current due to effective narrowing of energy band gap due to this. . To prevent this, it is necessary to take measures for protecting the end face in a separate post-process. Of course, there have been various proposals for the end face protection itself, such as making a non-current injection part on the end face,
There is such as covering with wide band gap material,
However, none of these methods is simple, and the production process is complicated.

In the conventional method 2 (wet etching method), when the composition of the member to be etched is uniform in the thickness direction, a facet having relatively high verticality (an end face cut out by etching) can be obtained. The disadvantage is that the facet angle changes depending on the composition. In other words,
It is always difficult to always obtain a vertical facet, especially in the case of a semiconductor laser using the above AlGaAs-based semiconductor material, where the Al composition differs along the thickness direction, as is commonplace. It cannot be applied to electronic devices that require a laminated structure.

[0007] Conventional method 3 (dry etching method) is disclosed in Japanese Patent Publication No.
As described in the above publication, the use of an ECR etching apparatus has the advantage that the substrate can be finely processed into an arbitrary plane shape without depending on the plane orientation, and the verticality of the cut facet can be improved. obtain. However, it is difficult to avoid damage due to the impact of accelerated ions remaining on the substrate surface after dry etching, and thus, as in the cleavage method, there is a possibility that COD may be caused. Further, in the case of the above-described semiconductor laser, in order to enhance the effect of confining carriers, the periphery (exposed side surface) of the laser active layer is preferably covered with a wide band gap semiconductor by crystal regrowth.
If the underlayer is damaged, a good crystal regrowth interface cannot be obtained, the characteristics are inevitably deteriorated, and there is also a problem that an end face protective film must be separately formed in a later step. In addition, the etching mask layer itself must be damaged by the collision of high-energy ions, and the thickness and shape of the mask itself must be strictly set according to the etching depth and the etching shape. Moreover, in order to obtain a vertical edge shape, the mask edge surface itself must be vertical, and it is not always easy to make the mask edge surface vertical when patterning this mask in a predetermined plane pattern. No, advanced, such as reactive ion etching
A high-precision technique must be used, which also has the drawback of complicating the manufacturing process.

On the other hand, in the case of the above-mentioned conventional method 4 (vapor phase etching method), the problem of substrate damage hardly needs to be considered, which is of course a favorable condition for the subsequent crystal regrowth. Since there is no ion bombardment or the like, there are few restrictions on the etching mask layer. On the other hand, as noted in this document, from the standpoint of obtaining a facet that is as perpendicular to the main surface of the substrate as possible for all III-V compound semiconductor systems, in the case of this vapor phase etching method, II including Al composition
Up to now, it has not been possible to obtain a sufficiently satisfactory vertical facet for IV group compound semiconductors, typically Al _x Ga _{1 -X} As based semiconductor materials.

The present invention has been made in view of the above circumstances and aims to cut out an end face as perpendicular as possible to the main surface of a III-V compound semiconductor while eliminating or at least mitigating the drawbacks of the conventional methods described above. Is to disclose a new identification method.

[0010]

Means for Solving the Problems In order to solve the above problems, the present inventor first went through the following consideration process. (1) The above-mentioned conventional methods 1 to 3 have fundamental and fundamental problems irrespective of the physical properties of the member to be etched. The physical cleavage method of the conventional method 1 and the collision of high energy ions of the conventional method 3 cannot be overturned.
In the case of the wet etching method of the conventional method 2, as described above, the etching shape differs depending on the Al composition so far, and there has been no successful example of overcoming this. In the future, if temporarily
Even if the etching conditions of the vertical end face irrespective of the Al composition are disclosed, for example, when manufacturing a future electronic device typified by the above-described semiconductor laser, industrially, manufacturing in a so-called vacuum integrated process, or Considering that it is desirable to go through a plurality of continuous steps in the same apparatus as much as possible, this is a technique that we do not want to adopt much. (2) On the other hand, the conventional method 4, on the contrary, except for the Al _X Ga _1-X As type compound semiconductor, is almost satisfactory vertical to the currently used semiconductor materials including GaAs and InAs. Facets can be obtained. Damage is small, and restrictions on the etching mask layer are loose. In addition, since the vacuum environment during crystal growth in a so-called MOCVD apparatus and that during vapor phase etching do not change much, the etching process and the subsequent crystal regrowth process can be performed simply by switching the gas type required for each. It is anticipated that this can be performed in the same chamber of the same MOCVD apparatus, and in particular, as described above, a structure that enhances the carrier confinement effect by covering the periphery of the laser active layer with a semiconductor having a wide energy band gap is obtained. This is a great advantage. This is, for example,
MOCVD when considered in combination with ECR etching equipment
Since the difference between the vacuum environment at the time and that at the time of dry etching is too large, etching and subsequent crystal regrowth cannot be performed in the same apparatus or the same chamber. In fact, Japanese Patent Publication No. 8-17230 has already taken this point into consideration and proposed an equipment structure that can transfer samples between an ECR etching apparatus and a MOCVD apparatus while maintaining a vacuum environment. ing. However, it is desirable to avoid the necessity of at least such ancillary equipment or ancillary equipment if possible. Of course, if such ancillary equipment is not used and the apparatus is taken out into the air environment and moved between the apparatuses, the problem of sample oxidation becomes serious, and the crystal quality at the time of crystal regrowth after etching cannot be guaranteed at all. (3) From these facts, it can be seen that, among the conventional methods, only the conventional gas phase etching method is the most promising method worthy of improvement. Its disadvantage, the disadvantage of "selecting the physical properties of the object to be etched", specifically, containing the Al composition III-
As long as the disadvantage that it cannot be applied to Group V compound semiconductors is eliminated, various III-V compound semiconductor-based microelectronic devices, such as a target semiconductor laser, can be manufactured with high yield and high quality at low cost by a fairly simple manufacturing process. In addition, it is suitable for integration.

The present inventor has conducted intensive studies based on such findings (3), and as a result, has come to the present disclosure. It has been difficult to obtain vertical facets by the conventional vapor phase etching method. As a processing technique that can be applied to III-V compound semiconductors containing an Al composition and that can be used as a mirror surface of a laser resonator, a facet perpendicular to a sufficiently satisfactory degree can be simply stated.・ Propose a method of performing vapor phase etching using an alkyl chloride gas as an etching gas.

In fact, according to this method, III-
Group V compound semiconductors, typically, for example, Al _X Ga _1-X As (0 ≦ x
<1: GaAs when x = 0), but succeeded in obtaining a facet closer to the true vertical as a plane orthogonal to the [0-1-1] direction in the substrate plane, and the Al composition It has been found that even if changes in the thickness direction of the structure (height direction of the facet), the effect is hardly affected and a sufficiently uniform vertical facet can be obtained. The verticality of this end face achieves the intended purpose,
It can be used completely as a laser resonator mirror surface of a semiconductor laser having a laser active layer extending in the [0-1-1] direction. The alkyl chloride gas used is preferably C ₂ H ₅ Cl gas or CH ₃ Cl gas.

Further, according to the present invention, the fundamental disadvantages of the conventional vapor phase etching method have been eliminated by the above-described basic structure, so that it is the most versatile and effective as a microelectronic device to be processed. III-V
When a group compound semiconductor laser is considered, a method of manufacturing a group III-V compound semiconductor laser by the following process group can be proposed as a process group partially including the above basic processing method.

That is, in a specific embodiment of the present invention, (a) a III-V compound semiconductor-based laser active layer and one or more III-V compound semiconductor-based layers located above and below it. At least, a planar pattern according to the planar shape of the III-V compound semiconductor laser, which is the structure to be cut, against the surface of the starting structure including the laminated structure necessary for manufacturing the III-V compound semiconductor laser And (b) etching the starting structure having the etching mask layer by vapor phase etching using an alkyl chloride gas as an etching gas to obtain a group III-V compound semiconductor laser. Cutting out the entire shape and cutting out end faces constituting a pair of mirror surfaces facing each other at both ends in the length direction at the same time. We propose a method for manufacturing a group III-V compound semiconductor laser.

Further, in the present invention, since the vertical end face is cut out by vapor phase etching, the crystal can be continuously regrown after the etching. Rather, the MOCVD apparatus used for crystal regrowth can be used for etching. This is because there is often no need to change other conditions by only changing the reaction gas. Therefore, also in this regard, the present invention provides, in addition to the above constitutional requirements (a) and (b), (c) the above vapor phase etching is performed in a MOCVD apparatus; III-V compound semiconductor laser characterized by forming a coating layer covering side and end faces of a laser active layer by recrystallizing a wide band gap III-V compound semiconductor in a MOCVD apparatus. We also propose a method of manufacturing.

In addition, the present invention also proposes, as a further lower aspect, various structural devices for the III-V compound semiconductor laser manufactured by the present invention as described in the gist of the present application. Is clear from the following description.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the steps of fabricating a group III-V compound semiconductor laser. In other words, the “structure of the III-V compound semiconductor having a main surface which needs to have an end face perpendicular to the main surface” in claim 1 of the present application, which defines the most basic configuration of the present application, is: In the description here, a III-V compound semiconductor laser is used. In addition, the “vertical end face” refers to the III-
It is a pair of laser resonator mirror surfaces that face each other at both ends in the length direction of the group V compound semiconductor laser.

First, FIG. 1A shows a starting structure 20 including a laminated structure necessary for finally fabricating a group III-V compound semiconductor laser on an appropriate substrate 10. Is formed. Although the physical properties of the substrate 10 are not limited in principle, considering the formation of the starting structure 20 which is a laminated structure of a III-V compound semiconductor based thereon, from the viewpoint of familiarity and convenience of manufacturing, This is also III-V
It is desirable to use a group III compound semiconductor. In the case where the structure to be finally manufactured is a semiconductor laser as exemplified here, it is common to attach an electrode also to the back surface of the substrate 10, and therefore, it is necessary that the substrate 10 has at least conductivity. Often required.

On the other hand, although the starting structure 20 previously formed on the substrate 10 does not show the internal cross-sectional structure in this drawing,
It is sufficient that the structure includes at least a III-V compound semiconductor based laser active layer and one or more III-V compound semiconductor based layers located above and below the laser active layer. This is not stipulated, and the manufacturing method is not particularly specified. Any existing or future cross-sectional structures and manufacturing methods may be followed.

However, in order to explain the embodiment of the present invention, it is easier to understand it in accordance with a specific example. Here, an example of the sectional structure of the starting structure 20 and its composition profile are shown in FIG. I will explain it. First, an n-GaAs substrate is used as the substrate 10, and an n-GaAs buffer layer 21, an n-AlGaAs cladding layer 22, and a
n-AlGaAs grease layer (guide layer) 23, MQW laser active layer (waveguide layer) 24 that forms several quantum well (MQW) structures by alternate lamination of GaAs and AlGaAs layers, p-AlGaAs grease layer
25, p-AlGaAs cladding layer 26, and p-GaAs cap layer 27
Are laminated by a suitable method, preferably, a MOCVD method, and the laminated structures 21 to 27 constitute a starting structure 20 in combination.

The Al _X Ga _1-X used in each layer
As for the number x of 0 or more and less than 1 representing the composition ratio of As, FIG.
In the upper and lower cladding layers 22 and 26,
The MQW laser active layer 24 is composed of a GaAs thin film having an Al composition number x = 0 and an AlGa having an Al composition number x = 0.2.
The Al _X Ga _1-X As grease layers 23 and 25 sandwiching the upper and lower sides of the MQW laser active layer 24 have an Al composition number x of 0.2 to 0.4, respectively, along the thickness direction. hand
The composition ratio is exponentially increased as the distance from the MQW laser active layer 24 increases. However, such a structure itself is already well known, and simply MQW
It is also called a semiconductor laser or the like, and various laminated structures, composition ratios, the number of quantum wells, and the like have been proposed. Incidentally, in the prototype of the present invention, the number of quantum wells in the MQW layer 24 is three.

On one main surface of the starting structure 20, an etching mask 30 having a pattern shape conforming to the plane shape of the structure to be finally cut is formed. In the embodiment assumed here, The structure to be obtained is an AlGaAs-based MQW edge-emitting semiconductor laser, which has the above-described starting structure 20 having a laminated structure. Therefore, in the prototype manufactured by the inventor of the present invention, as shown in FIG. to, by a thermal CVD method, after depositing the SiO ₂ film is set on one major surface of the starting structure 20, by well-known conventional lithography, to form the SiO ₂ film pattern of H-type or ladder An etching mask layer 30 having a predetermined pattern was formed. Here, the extending direction of a portion 31 (hereinafter simply referred to as a beam 31) of the ladder corresponding to a so-called beam is represented by [0-1-
1], and naturally, the direction in which the portion 32 (hereinafter, simply the handrail 32) corresponding to the handrail supporting both ends of the crosspiece 31 extends is a direction orthogonal to this. As will be readily apparent, a beam 31 is a pattern portion for substantially cutting out a main structural portion for determining the light amplification and oscillation path of the light of the stripe-shaped semiconductor laser, and a handrail 32 extending in a direction perpendicular to the pattern portion.
Is a pattern portion as a manifestation of a device for maintaining good flatness of an end face constituting a laser resonator mirror surface of the semiconductor laser, as described later.

After the etching mask 30 having a predetermined pattern is formed as described above, if necessary, the surface is washed with hydrochloric acid and ultrapure water. Then, an alkyl chloride gas, which is a characteristic step of the present invention, is removed. Vapor phase etching as an etching gas is performed.

Under the limitation that an alkyl chloride gas is used as an etching gas, the conditions at that time can be arbitrarily changed to a considerable extent, and the alkyl chloride gas to be used is preferably C ₂ H ₅ Cl or In addition to CH ₃ Cl gas, other alkyl chloride gas may be used. For example, in the prototype of the present inventor, the same MOC as that used to form the starting structure 20 was used.
C ₂ H as alkyl chloride gas in the chamber of the VD device
_{Using 5} Cl, a considerable number of vapor phase etchings within the following condition range were attempted. Substrate temperature: 500 to 700 ° C Hydrogen carrier gas flow rate: about 4 SLM Chamber internal pressure: about 0.1 atm C ₂ H ₅ Cl concentration: about 2.4 to 2.6% C ₂ H ₅ Cl flow rate: 30 to 60 sccm Etching time: Depends on the thickness of each layer n-AlGaAs cladding layer
Around 22

Through this step, as shown in FIG. 1C, a striped semiconductor laser as a structure to be obtained is obtained.
If the above-mentioned main structural part 41 having a length in the [0-1-1] direction is cut out at the same time as the entire structure of the ladder 40, and if the main structural part 41 is also used as a ladder crosspiece, the crosspieces are formed on both sides thereof. The end stripe structure portions 42, 42 corresponding to a pair of handrails extending in a direction perpendicular to the direction of the handrail are cut out. As a result of following the procedure of the present invention, the etch facets or end faces 43, 43, which are the outer surfaces in the vertical direction of the end stripe structure portions 42, 42, are oriented with respect to the [0-1-1] direction. Vertical to a satisfactory degree. Moreover, it is also important that even if the Al composition differs in the thickness direction as in the cross-sectional structure example shown in FIG. It does not matter, and a smooth vertical surface is formed. Therefore, the vertical end faces 43, 43 thus formed are formed.
Are good enough to form a pair of laser resonator mirror surfaces at both ends of the main structural portion 41 of the MQW semiconductor laser, which necessarily includes layers of different Al compositions. Of course, of all the end face portions of the end stripe structure portions 42, 42, only an area having a width Wp which is a part of the length direction and located at both ends of the semiconductor laser main structure portion 41 becomes a mirror surface of the semiconductor laser. The other portions outside the above do not particularly contribute to the operation of the semiconductor laser, but the reason for this (the reason for forming the ladder type) is, as described above, a little later. Further, the proof of how the vertical end face is formed is made by referring to FIG. 6 which is substituted by a scanning electron micrograph after the manufacturing process of the semiconductor laser of the present embodiment, and this will also be described later.

If the entire structure of the semiconductor laser 40 in this case, which is the target structure, is cut out by the vapor phase etching step, the vapor phase etching is desirably performed in the present invention as described above. If it is inside a MOCVD apparatus, it is not necessary to take it out of this apparatus, and it is possible to continuously apply them to a wide band including not only the outer periphery of the main structural part 41 of the semiconductor laser but also the end faces 43 and 43 constituting the mirror surface. It can be embedded by a gap III-V compound semiconductor crystal covering layer. That is, unlike the conventional dry etching method or the like, the environment in the MOCVD apparatus at the time of crystal growth is different from that at the time of the vapor phase etching according to the present invention in the extent that the reaction gas used is different, and does not require a great change in environment. Therefore, crystal regrowth can be performed in the same apparatus (as described above, since the starting structure 20 is constructed in the first place, the recrystallization is performed in the same MOCVD apparatus).

In fact, even in the prototype of the present inventor, immediately after the step of FIG. 1 (C), the gas was switched immediately in the same MOCVD apparatus chamber, and only AsH ₃ was flowed for about 5 minutes. After exhaust processing, also flow TMAl and TMGa gas,
As shown in FIG. 1D, by forming a coating layer 50 of an AlGaAs crystal regrowth layer, substantially the entire semiconductor laser 40 was buried. In other words, as in the prior art, the danger of contact with the atmospheric environment can be eliminated, or a special transfer device or the like that was conventionally required to prevent such exposure can be eliminated. . Moreover, since the underlayer for crystal regrowth is exposed only to the gas phase etching environment, there is almost no damage, and a high quality crystal regrowth interface can be obtained. You do not need to think about previous problems that occur. Regarding the latter, the fact that the exposed side surface of the laser active layer and the mirror surface serving as the emission end surface can be simultaneously protected, rather than a separate step, are extremely significant effects in terms of simplification of the manufacturing process and improvement of characteristics.

FIG. 2 shows a step group subsequent to the above-mentioned characteristic step group of the present invention. First, as shown in FIG. 2A, a protective film 52, for example, SiO ₂
After the film 52 is formed over a suitable thickness by a suitable method such as a thermal CVD method, as shown in FIG. A window 53 for forming an electrode is opened at a certain point (generally, on the upper surface at the center of the semiconductor laser main structure portion 41 which is also at a geometrically uniform position), and then as shown in FIG. Surface electrode 54 (eg, Au / Cr) which is in ohmic contact with the uppermost p-GaAs cap layer 27 in the cross-sectional structure.
Layer) is vapor-deposited on a predetermined pattern.

Thereafter, the back surface (the back surface of the substrate 10) is polished through an alloying step or the like as necessary, and then an appropriate metal material such as AuGe / Ni / Au is formed on the back surface of the substrate by vapor deposition. After an alloying step or the like is performed as necessary, as shown in FIG. 3, a target III-V compound semiconductor embedded structure type etch facet semiconductor laser 40 is completed. Although the laser emission end face 43 is also covered with the SiO ₂ layer, it does not cause any problem except that it is desirable because it has a protective function.

However, the manufactured semiconductor laser 40 is
When viewed two-dimensionally, it has a ladder shape as described above. This is for the following reason. As shown in FIG. 5 (A), if a stripe-shaped semiconductor laser is to be obtained, a simple straight line is formed over the entire length of the semiconductor laser without providing an end stripe structure portion corresponding to a handrail of a ladder on the end surface. If it is cut out into a shape, the pattern shape of the etching mask layer at that time is a simple rectangle as indicated by reference numeral 30 '. However, in the shape of the semiconductor laser 40 'cut out via the etching mask layer 30', the corner C at the end of the semiconductor laser 40 '"drops off" even by vapor phase etching. In this case, naturally, the end face of the semiconductor laser cannot be said to be an ideal resonator mirror surface.

Therefore, the main structural part of the semiconductor laser 40 is
At both ends in the length direction of 41, an end stripe structure portion 4 extending in a direction orthogonal to the direction in which the main structure portion 41 extends.
2, 42 were provided. As a result, as shown in FIG. 5B, in the semiconductor laser 40 cut out through the ladder-type etching mask layer 30, the angle C at the end of the handrail, which is substantially unrelated to the laser operation, is formed. Even if the angle drops, the flatness of the effective end face portion having the width Wp that should form the resonator mirror surface can be kept very good.

FIG. 5C shows that this ladder structure is advantageous when a plurality of semiconductor lasers are integrated. Principal structural parts 41 of a plurality of semiconductor lasers 40 arranged side by side in a plan view.
This is because the pair of end stripe structures 42, 42 can be shared by all. It is easy to increase the integration density. In such an integrated structure, the overall planar shape literally looks like a ladder with multiple bars or steps.

FIG. 6A shows a scanning electron micrograph of an end face of a structure corresponding to the semiconductor laser 40 manufactured according to the method described with reference to FIGS. FIG. 6B is a drawing extracted from FIG. As is apparent from FIG. 6, according to the method of the present invention,
Sufficiently vertical end face despite gas phase etching
43 are formed. Note that the side surface of the stripe laser structure portion is substantially a (111) B plane.

As described above, the present invention is not applied only to fabricating a stripe-shaped semiconductor laser.
Although there is a restriction that the end face is orthogonal to the [0-1-1] direction,
It can be widely applied to the fabrication of a group III-V compound semiconductor structure requiring a vertical end face. Also, when the semiconductor laser belongs to the semiconductor laser category, it can be applied to the production of a semiconductor laser having various functions corresponding to an arbitrary structural principle. For example, as shown in FIG. It is not simply a stripe of the same width, but a narrow part 61 and a wide part 6
2, a multi-mode laser 60 comprising a plurality of parallel output portions 63 extending from the widened portion 62 can also be constructed. Since the structure and operation principle are well known, detailed description is omitted, but the widened portion functions as a multimode waveguide, and can be used as a high-power laser. Various numbers and lengths of the widened portion provided in at least a part of the length direction of the semiconductor laser can be considered.

In the case of FIG. 8, the main structural part may be the same as that of FIG. 7, but the surface electrode 54 previously described with reference to FIGS. As a result of being divided into the carrier injection electrode portions 71, 72, the carriers injected through them are turned on and off, or the amount of injected carriers (applied current value) through them is varied, so that a plurality of carriers are injected. The laser beam can be selectively emitted from any one of the output lines 73, or can be used as a beam deflecting laser 70 for deflecting the emission angle.

[0036]

According to the present invention, vapor phase etching can be used to obtain a vertical end face in a III-V compound semiconductor based structure. Each of the disadvantages has been almost eliminated, and various excellent effects can be enjoyed as described below. (1) The present invention can be applied to a III-V group compound semiconductor containing an Al composition, and an end face with extremely high perpendicularity can be obtained regardless of the Al composition. (2) An extremely good vertical end face can be formed without being damaged by ion bombardment or the like. Therefore, particularly when applied to the manufacture of a semiconductor laser, a semiconductor laser having a resonator mirror surface without damage can be manufactured. Considering also the above effect (1), it is extremely effective for forming a resonator mirror surface of a III-V compound semiconductor laser including a quantum well structure. (3) Since there is no damage, a good crystal regrowth interface can be obtained even when crystal regrowth is performed on the surface after etching, and various characteristics of various electronic devices that are manufactured structures are improved. Or at least does not cause a characteristic deterioration. Similarly, as described above, when applied to the fabrication of a group III-V compound semiconductor laser, an extremely good buried structure not only on the side surface of the active layer but also on the entire circumference can be obtained. (4) Etching can be performed in the MOCVD equipment if necessary.
When fabricating a structure that requires process D, there is no need to take out the sample in the process of fabrication outside the MOCVD device for the etching process, and a series of processes can be performed in the same device. Significantly simplified. The problem of contamination due to oxidation can be avoided, and no separate device or equipment is required to prevent exposure to the atmosphere. When fabricating the above-described embedded structure type semiconductor laser, there is also a considerable advantage that the entire circumference embedded structure can be formed uniformly. (5) It is not necessary to consider the damage of the etching mask layer, and it is released from various severe restrictions on the etching mask layer as in the conventional dry etching. This eliminates the need to pay strict attention to the thickness of the etching mask and the perpendicularity of the end face. This also simplifies the manufacturing process. (6) When applied to the fabrication of a semiconductor laser, an end face protective film can be formed simultaneously with the coating of the side face portion of the active layer, so that the vertical end face formed with good quality can be promptly protected. This also significantly simplifies the manufacturing process, since no need is made. (7) Needless to say, there is no principle factor for lowering the integration density as in the case of the cleavage method. Rather, even if the elements are adjacent to each other, there is little cause for deterioration in the characteristics, so this method is suitable for improving the integration density.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a part of a semiconductor laser manufacturing step including a characteristic step according to the method of the present invention.

FIG. 2 is an explanatory view of a manufacturing process of the semiconductor laser from FIG. 1 to immediately before completion.

FIG. 3 is a schematic perspective view of a semiconductor laser manufactured according to the steps of FIGS.

FIG. 4 is an explanatory diagram of an example of a cross-sectional structure of the semiconductor laser shown in FIGS.

FIG. 5 is an explanatory diagram of a relationship between an etching mask pattern and a structural shape cut out based on the etching mask pattern, and a semiconductor laser formed side by side in a ladder shape.

FIG. 6 is a diagram illustrating a scanning electron beam photograph as a drawing substitute photograph of an end face portion of an example of a structure manufactured according to the present invention, and an outline of the scanning electron beam photograph.

FIG. 7 is a schematic configuration diagram of a multimode laser that can be manufactured according to the present invention.

FIG. 8 is a schematic configuration diagram of a beam deflection laser that can be manufactured according to the present invention.

[Explanation of symbols]

 10 Substrate 20 Starting structure 21 n-GaAs buffer layer 22 n-AlGaAs cladding layer 23 n-AlGaAs green layer 24 MQW laser active layer 25 p-AlGaAs green layer 26 p-AlGaAs cladding layer 27 p-GaAs cap layer 30 etching mask Layer 31 Beam 32 Handrail 40 Semiconductor laser 41 Main structure of semiconductor laser 42 Edge stripe structure 43 End face (resonator mirror surface) 50 Crystal formation long layer 52 Protective film 53 Window 54 Surface electrode 55 Back electrode 60 Multi-mode laser 61 Narrow part 62 Wide part 70 Beam deflection laser 71 First electrode part 72 Second electrode part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasunori Okamoto 1-1-1, Hama, Amagasaki-shi, Hyogo Inside Kubota Research Institute of Technology (72) Inventor Seishi Igawa 1-1-1, Hama, Amagasaki-shi, Hyogo Co., Ltd. Kubota Technology Development Laboratory

Claims (15)

[Claims] In producing a structure of a group III-V compound semiconductor having a main surface which needs to have an end face perpendicular to the main face, the III-V compound semiconductor is formed to form the vertical end face.
A method of processing a group III compound semiconductor, which has a shape that matches the plane shape of the above-mentioned structure when viewed two-dimensionally, and is in the [0-1-1] direction along a position where the above vertical end face is to be formed. Forming an etching mask layer having an edge perpendicular to the above on the group III-V compound semiconductor; performing gas phase etching using an alkyl chloride gas as an etching gas; II
A method for processing an IV compound semiconductor. 2. The method for processing a III-V compound semiconductor according to claim 1, wherein the III-V compound semiconductor has an Al composition. . 3. The method for processing a group III-V compound semiconductor according to claim 2, wherein x is 0.
A method of processing a group III-V compound semiconductor, characterized in that the semiconductor is an Al _X Ga _{1 -X} As-based semiconductor having a numerical value less than 1 or more. 4. The method for processing a group III-V compound semiconductor according to claim 1, 2 or 3, wherein the alkyl chloride gas is a C ₂ H ₅ Cl gas or a CH ₃ Cl gas. III-V compound semiconductor processing method. 5. III-V according to claim 1, 2, 3, or 4
A method for processing a group III compound semiconductor;
A semiconductor laser having a length in the [0-1-1] direction; the vertical end faces constituting a pair of laser resonator mirror surfaces facing each other at both ends in the length direction of the semiconductor laser;
A method for processing a group III-V compound semiconductor, comprising: 6. A method for manufacturing a III-V compound semiconductor laser, comprising: a III-V compound semiconductor-based laser active layer;
Cut out the surface of the starting structure including at least one layer of a III-V compound semiconductor based on at least one layer and including a laminated structure necessary for manufacturing a III-V compound semiconductor laser. Forming an etching mask layer having a planar pattern according to the planar shape of the III-V compound semiconductor laser, which is the structure to be formed; and using the starting structure having the etching mask layer with an alkyl chloride gas as an etching gas. Etching by vapor phase etching to cut out the overall shape of the group III-V compound semiconductor laser and, at the same time, cutting out end faces constituting a pair of mirror surfaces facing each other at both ends in the longitudinal direction. A method for manufacturing a group III-V compound semiconductor laser, comprising: 7. The method for fabricating a group III-V compound semiconductor laser according to claim 6, wherein said gas phase etching is MOCVD.
Performed in the apparatus; after the vapor phase etching, the M
Forming a coating layer covering the side face and the end face of the laser active layer by recrystallizing a wide band gap III-V compound semiconductor in an OCVD apparatus; A method for manufacturing a semiconductor laser. 8. The method of manufacturing a group III-V compound semiconductor laser according to claim 6, wherein end stripe structures extending in a direction perpendicular to the length direction are formed at both ends of the semiconductor laser. A III-V compound semiconductor laser, wherein the vapor phase etching is performed so as to be formed; a part of the length of the end face of the pair of end stripe structures constitutes the mirror surface. Production method. 9. The method for fabricating a group III-V compound semiconductor laser according to claim 8, wherein the semiconductor lasers include a plurality of semiconductor lasers which are juxtaposed in a plan view; Has an end stripe structure portion common to the plurality of semiconductor lasers; thereby, each of the pair of end stripe structure portions corresponds to the shape of a handrail of a ladder, and each semiconductor laser between them has A III-V compound semiconductor laser, characterized in that the semiconductor laser has a shape corresponding to the cross section of the ladder, and as a whole, has a ladder shape in which a plurality of semiconductor lasers are integrated in a side-by-side relationship. Method of manufacturing. 10. III- according to claim 6, 7, 8 or 9
A method for manufacturing a group V compound semiconductor laser, wherein the semiconductor laser has a stripe shape having a constant width in the length direction. 11. The III- according to claim 6, 7, 8 or 9.
A method for manufacturing a group V compound semiconductor laser, wherein the semiconductor laser is a semiconductor laser having a shape having a different width in at least a part of the length direction and capable of multi-mode operation. Method for manufacturing group V compound semiconductor laser. 12. III- according to claim 6, 7, 8 or 9
A method of manufacturing a group V compound semiconductor laser, wherein the semiconductor laser has a plurality of carrier injection electrodes, and the amount of carriers injected into the plurality of carrier injection electrodes is changed to change the emission position of an emission beam. Or a semiconductor laser having a function capable of deflecting the emission direction; and a method of manufacturing a group III-V compound semiconductor laser. 13. The method of claim 6, 7, 8, 9, 10, 11, or
13. A method for manufacturing a group III-V compound semiconductor laser according to item 12, wherein the group III-V compound semiconductor contains an Al composition. 14. A group III-V compound semiconductor laser manufacturing method according to claim 13; said group III-V compound semiconductor was numerically less than 1 0 or an x Al _X Ga _1-X As A method of manufacturing a group III-V compound semiconductor laser. 15. The method of claim 6, 7, 8, 9, 10, 11, 12,
15. A method for producing a III-V compound semiconductor laser according to 13 or 14, wherein the alkyl chloride gas is a C ₂ H ₅ Cl gas or a CH ₃ Cl gas. Method of manufacturing.