JP2001077468A - Manufacture of edge-emitting type semiconductor laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an edge emitting type semiconductor laser having a small size and low power demand. SOLUTION: The figure shows the top view of the end section of the resonator of an end-emitting type semiconductor laser. When widths (d) and D of the end section on a resist mask forming pattern are respectively set to satisfy d≈2δ and D≈W+2δ (where δ is the etching loss length of the corners of the end section), the etched shape of the end section becomes the as shown in Fig. (b), satisfying the expression, F=W. Consequently, power consumption and quantity of heat of the resonator are reduced, because the areas of the left and right projecting sections αand β of the I-shaped portion of the resonator in the top view are suppressed to small values, and accordingly, current constriction can sufficiently easily occur in the end section and the damned current of the resonator becomes smaller. In addition, since the interval between the resonator and a negative electrode can be reduced and the current path between electrodes become shorter, the resistance value of the laser diode of this laser is reduced, and by the reduced resistance value, the power consumption and quantity of heat are also suppressed to small values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an edge-emitting laser diode using a group III nitride compound semiconductor, and more particularly to a method for forming an end face of a resonator of an edge-emitting laser diode.

[0002]

2. Description of the Related Art FIG. 4 is a schematic perspective view (design drawing) of an edge emitting semiconductor laser 900 according to the prior art in a design stage. A buffer layer 102 made of aluminum nitride (AlN) is formed on a sapphire substrate 101, and a semiconductor layer made of a group III nitride-based compound semiconductor is further provided thereon with a high carrier concentration n ^+. Layer 10
3, n-type cladding layer 104, n-type doped InG
n-type optical waveguide layer 105 made of aN, MQW active layer 106 in which well layers made of InGaN and barrier layers made of GaN are alternately stacked, p-type optical waveguide layer 107 made of p-doped InGaN, p Mold cladding layer 108, p
The contact layers 109 are sequentially stacked.

A negative electrode 140 is formed on the high carrier concentration n ⁺ layer 103 exposed by etching, and a positive electrode 120 is formed on the p-type contact layer 109 by metal deposition. The present edge emitting semiconductor laser 900 is of a mesa stripe type, and its resonator is shaped like a capital letter “I”, and is characterized in that the width D of the emitting edge is wide.

FIG. 5 shows a plan view of a cavity end portion of this conventional edge emitting semiconductor laser 900. As shown in FIG. Hereinafter, the following symbols are used. (Symbols) c1, c2, c3, c4... Angle of resonator end on resist mask forming pattern α, β... I-shaped protrusion of resonator end to right and left D... On resist mask forming pattern The width d of the cavity end face of the resonator is perpendicular to the cavity end face of the cavity end (α, β) W The width of the mesa stripe of the light emitting portion main body of the cavity F… The width δ of the cavity end face after etching processing Cut length of corner of resonator due to etching

FIG. 5A shows a pattern for forming a resist mask at the end of the resonator when the resonator is formed by etching. FIG. 5B shows the shape of the end portion of the resonator after the etching process when etching is performed using the resist mask of FIG.

As shown in FIG. 5, when etching is performed, the corners c1, c2, c3, and c4 of the resonator end on the resist mask forming pattern are determined by the exposure accuracy of the exposure apparatus using UV light. Due to the limit, it is slightly cut during the etching process, and is actually rounded. The value of the cutting length δ depends on the wavelength of the electromagnetic wave used. Also,
Usually, such an exposure apparatus uses UV to reduce its cost.
Those using light or the like are generally used.

Under such conditions, the value of the mesa stripe width W of the light emitting portion body of the resonator when the conventional edge emitting semiconductor laser 900 is manufactured is approximately 0.1 to 5 μm. On the other hand, the value of the abrasion length δ at the corner of the resonator end due to etching is generally about 0.5 to 1 μm.

In such a conventional edge emitting semiconductor laser 900, the width D of the cavity facet on the resist mask forming pattern is increased so that the following equation (1) is sufficiently satisfied with respect to the abrasion length δ. By ensuring, the flatness of the end face is ensured.

F = D−2δ> W (1)

FIG. 6 shows a plan view of a semiconductor laser 900 actually subjected to the etching process and thereafter provided with electrodes. In the semiconductor laser 900, the width D is ensured to be sufficiently large and “F <W” is not satisfied, and the flat and parallel end faces can be sufficiently widened. Oscillation is confirmed. That is, when the resonator is formed in a capital letter "I" shape when viewed from a direction perpendicular to the substrate surface (above the crystal growth direction), and the ends (projections α, β) are enlarged, the above-described effect is obtained. Certain structures are specifically configured.

[0010]

However, in the conventional semiconductor laser 900 as described above, the area viewed from above the protrusions α and β at the end of the resonator is large, and the vertical direction (crystal Since the surface density of the current flowing in the (growth direction) becomes low, the current confinement near the end of the resonator becomes insufficient. For this reason, a problem arises in that the current required for laser oscillation increases.

Further, the distance L between the resonator and the negative electrode 140
However, since the width increases with the width D, the current path between the positive electrode 120 and the negative electrode 140 increases, and the resistance of the light emitting element (laser diode) increases. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to manufacture an edge-emitting semiconductor laser which requires less power for laser oscillation and has a smaller physical size. Is to provide a way.

[0013]

In order to solve the above-mentioned problems, the following means are effective. That is, the first means is to form a plurality of semiconductor layers made of a group III nitride compound semiconductor on a substrate by crystal growth, and to remove a peripheral portion thereof by etching while leaving a resonator portion, so that a crystal growth direction is obtained. In the manufacturing process of the edge-emitting semiconductor laser in which the shape of the resonator viewed from above is formed into an I-shaped mesa stripe type, the width D of the end face of the resonator in the formation pattern of the resist mask for etching the resonator, It is set to be longer than the width W of the mesa stripe parallel to the end face of the light emitting portion main body of the resonator by about 2.0 to 2.2 times the cutting length δ due to etching of the corner of the edge of the end face viewed from above. It is.

[0014] The second means is the first means, wherein the width d in the direction perpendicular to the end face of the left-right protruding portion having the I-shaped end face in the formation pattern is defined as a cutting length δ. Is about 2.0 to 2.2 times.

[0015] Further, the third means may be the first or the second means.
Means, each group III nitride-based compound semiconductor layer
_x Ga _y In _1-xy N is (0 ≦ x, 0 ≦ y , x + y ≦ 1) to form from. With the above means, the above-mentioned problem can be solved.

[0016]

FIG. 1 is a plan view of a cavity end portion of an edge-emitting type semiconductor laser illustrating the operation of the present invention. By means of the present invention, for example, the widths d and D in the respective directions on the resist mask forming pattern at the end portions of the resonator are set so as to satisfy the following expressions (2) and (3), respectively (FIG. 1 (a)), the etched shape of the end of the resonator has a shape as shown in FIG. 1 (b). At this time, the etched shape at the end of the resonator satisfies the following equation (4).

[0017]

## EQU2 ## d ≒ 2δ (2)

D３W + 2δ (3)

[Expression 4] F ≒ W (4)

As described above, according to the means of the present invention, the area when viewed from above the left and right protrusions α and β of the I-shape of the resonator can be suppressed to be small, and the current in the resonator can be reduced. Stenosis is more likely to occur.

FIG. 2 is a plan view of an edge-emitting semiconductor laser illustrating the effects of the present invention. For example, by forming the end of the oscillator in this way, as shown in FIG.
In the laser diode of the present invention, the protrusions α and β are formed smaller than the edge emitting semiconductor laser 900 according to the prior art of FIG. 6, so that the current required for laser oscillation due to current constriction can be small. , Power consumption and calorific value are small.

The distance L between the resonator and the negative electrode 140
However, the current path between the positive electrode 120 and the negative electrode 140 is shortened. For this reason, the laser diode of the present invention has a small resistance value, which can also reduce power consumption and heat generation.

The width S of the laser diode of the present invention as shown in FIG. 2, for example, can be made smaller than that of the conventional edge emitting semiconductor laser 900 shown in FIG. 6 by optimizing the width D. . As a result, the number of laser diodes that can be cut from one semiconductor wafer can be greatly increased, and the productivity can be improved, and the laser diodes can be further reduced in size.

In particular, the semiconductor laser is made of Al _x Ga ₁ -xN
(0 ≦ x ≦ 1) and a cladding layer of Ga _y In _1-y N
The output of the blue short-wavelength laser diode can be improved by mainly configuring (0 ≦ y ≦ 1) / an active layer having an MQW structure of GaN.

It should be noted that the above operation and effect are at least
_{x Ga y In 1-xy N} (0 ≦ x, 0 ≦ y, x + y ≦ 1)
Can be obtained for a general mesa-stripe-shaped end-emission type III-nitride compound semiconductor laser diode in which a semiconductor layer composed of a binary, ternary or quaternary semiconductor represented by . Some of these Group III elements may be replaced with boron (B) and thallium (Tl), and some of nitrogen (N) may be replaced with phosphorus (P), arsenic (As), and antimony (Sb). ), Bismuth (Bi).

Further, using these semiconductors, n-type III
When forming a group nitride-based compound semiconductor layer, Si, Ge, Se, Te, C, or the like can be added as an n-type impurity. The p-type impurities include Zn, Mg, Be, Ca, S
r, Ba, etc. can be added.

Further, sapphire, spinel, Si, SiC, Zn are used as substrates for crystal growth of these semiconductor layers.
O, MgO, a group III nitride compound single crystal, or the like can be used. In addition to the aluminum nitride (AlN), generally, Al _x Ga ₁ -xN (0 ≦ x ≦ 1) crystal grown at a low temperature can be used for the buffer layer.

As a method of growing these semiconductor layers by crystal, molecular beam epitaxy (MBE), metal organic chemical vapor deposition (MOCVD), and halide vapor deposition (HDD) are used.
VPE), a liquid phase growth method and the like are effective.

As a material of a reflective metal film formed on the side wall of the oscillator via an insulating film or a material of a positive electrode, Al, In, Cu, Ag, Pt, Ir, Pd, Rh, W, M
o, Ti, Ni, or an alloy containing one or more of these can be used.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on specific embodiments. FIG. 3 is a perspective view of the edge emitting semiconductor laser 100 according to the present embodiment. On the sapphire substrate 101, a buffer layer 102 of aluminum nitride (AlN) having a thickness of about 200 ° is provided, and a high carrier concentration n ⁺ layer of silicon (Si) doped GaN having a thickness of about 4.0 μm is provided thereon. 103 is formed.

Then, on the high carrier concentration n ⁺ layer 103, an n-type cladding layer 104 of silicon (Si) -doped Al _0.10 Ga _0.90 N having a thickness of about 1 μm is laminated.
An n-type optical waveguide layer 105 having a thickness of about 0.2 μm is laminated thereon. The present n-type optical waveguide layer 105 is made of silicon (Si)
An n-type first type guide layer 1051 made of doped In _0.05 Ga _0.95 N and having a thickness of about 0.1 μm, and silicon (Si) doped Ga
N-type second type guide layer 105 made of N and having a thickness of about 0.1 μm
2 are sequentially formed to form a total of two layers.

Further, a Ga _0.8 In film having a thickness of about 30 ° is further formed thereon.
The MQW active layer 106 has a multiple quantum well structure in which well layers 1061 made of _0.2 N and barrier layers 1062 made of GaN having a thickness of about 70 ° are alternately stacked. That is, the three well layers 1061 and the two barrier layers 1062 are alternately stacked to form a total of five layers and a thickness of about 2 layers.
A 30 ° MQW structure is configured.

On the MQW active layer 160, a film thickness of about
A 0.2 μm p-type optical waveguide layer 107 is laminated. Book p
Type optical waveguide layer 107 is made of GaN doped with magnesium (Mg).
P-type second type guide layer 1072 having a thickness of about 0.1 μm
And a p-type first type guide layer 1071 made of magnesium (Mg) -doped In _0.05 Ga _0.95 N and having a thickness of about 0.1 μm are sequentially formed to form a total of two layers.

Further, on the p-type optical waveguide layer 107,
Magnesium (Mg) doped Al_0.10Ga _0.90Film thickness consisting of N
A p-type cladding layer 108 of about 1 μm is laminated. Sa
Furthermore, magnesium (Mg) is formed on the p-type cladding layer 108.
Approximately 600 ° thick p-type contact made of doped GaN
Layer 109 is formed.

Furthermore, the positive electrode 120 is formed by metal deposition on the p-type contact layer 109, also, n ⁺ layer 1
A negative electrode 140 is formed on 03. Positive electrode 12
0 is a film thickness of about 0.3 μm to be joined to the p-type contact layer 109.
A first metal layer made of rhodium (Rh) or platinum (Pt), a second metal layer made of gold (Au) having a thickness of about 1.2 μm formed on the first metal layer, and a second metal layer made of gold (Au). A third metal layer 3 of titanium (Ti) having a thickness of about 30 ° formed on the metal layer.
It has a layer structure.

The negative electrode 140 having a two-layer structure has a thickness of about 175 °.
Vanadium (V) layer and aluminum (A
l) layers are sequentially laminated on the partially exposed portion of the high carrier concentration n ⁺ layer 103. As described above, the edge emitting semiconductor laser diode 100 was configured.

The laser diode 1 thus configured
The plan view of 00 is as shown in FIG. 2 earlier, and the resonator portion is formed in a substantially “I” shape. From a part of the high carrier concentration n ⁺ layer 103, a p-type contact layer 109 is formed.
Each of the semiconductor layers described above constitutes this resonator. In this “I” -shaped element, the current constriction portion at the center is represented by the main body and the width is represented by W. The width W of the resonator body of the laser diode 100 in this embodiment is about 2
μm, and the cut length δ at the corner of the resonator end is about 0.8 μm.

Next, a method for manufacturing a light emitting device (semiconductor laser) having this structure will be described. The laser diode 100 is formed by metal organic compound vapor deposition (hereinafter referred to as “MOVPE”).
"). The gases used here were NH ₃ and carrier gas H ₂ or N ₂ , trimethylgallium (Ga (CH ₃ ) ₃ ) (hereinafter referred to as “TMG”) and trimethylaluminum (Al (CH ₃ ) ₃ ) (hereinafter referred to as “TMG”). It referred to as "TMA") and trimethyl indium _{(In (CH 3) 3)} ( hereinafter "TMI"
And silane (SiH ₄ ) and cyclopentadienyl magnesium (Mg (C ₅ H ₅ ) ₂ ) (hereinafter referred to as “CP ₂ Mg”).

First, a single crystal sapphire substrate 101 is treated with MOVP by using the a-plane cleaned by organic cleaning and heat treatment as a main surface.
E Attach to the susceptor placed in the reaction chamber of the device. Next, the sapphire substrate 101 was baked at a temperature of 1100 ° C. while flowing H ₂ at a normal pressure and a flow rate of ₂ liter / min into the reaction chamber for about 30 minutes.

Next, by lowering the temperature to 400 ° C., H ₂
20 liter / min, NH ₃ 10 liter / min, TMA 1.8 ×
The buffer layer 102 of AlN was formed to a thickness of about 50 nm by supplying at a rate of 10 ^-5 mol / min for about 90 seconds. Then, maintaining the temperature of the sapphire substrate 101 to 1150 ° C., 20LI of H ₂
ter / min, NH ₃ at 10 liter / min, TMG at 1.7 × 10 ^-4 mol / min, silane diluted to 0.86 ppm with H ₂ gas
(SiH ₄ ) was introduced at 20 × 10 ⁻⁸ mol / min, and the film thickness was about 4.0.
A high carrier concentration n ⁺ layer 103 made of GaN doped with silicon (Si) having a thickness of 1 μm, an electron density of 1 × 10 ¹⁸ / cm ³ , was formed.

The above high carrier concentration n⁺Form layer 103
After that, the temperature was kept at 1100 ° C._Two20li
ter / min, NH_Three10 liter / min and TMA 5.0 × 10^-6Mo
/ Min, TMG is 5.0 × 10^-FiveMol / min, H_TwoBy gas
Silane diluted to 0.86 ppm (SiH_Four) To 8 × 10^-9
Introduced at mol / min, film thickness 500 nm, electron density 1 × 10
¹⁸/ Cm^Three, Silicon (Si) doped Al_0.1Ga_0.9Consisting of N
An n-type cladding layer 104 was formed.

Next, the temperature was maintained at 1100 ° C. and N ₂ or
Diluted with H ₂ , NH ₃ , TMG, TMI and H ₂ gas (S
iH ₄ ) to supply silicon (Si) -doped Ga _0.95 In _0.05 N
N-type first type guide layer 1051 having a thickness of about 0.1 μm
Was formed. In addition, H2 is ₂₀ liter / min and TMG is 5 × 10
^-5 mol / min, it was diluted to 0.86ppm in H ₂ gas (S
iH ₄ ) was introduced at 8 × 10 ⁻⁹ mol / min, and the film thickness was 100 nm.
Silicon (Si) doped GaN with electron density of 1 × 10 ¹⁸ / cm ³
N-type second type guide layer 1052 of about 0.1 μm in thickness
Was formed.

Next, N ₂ or H ₂ , NH ₃ , TMG and TMI are supplied to form a well layer 1 of Ga _0.8 In _0.2 N having a thickness of about 30 °.
061 was formed. Next, N ₂ or H ₂ , NH ₃ and TMG were supplied to form a barrier layer 1062 made of GaN and having a thickness of about 70 °. Further, the well layer 1061 and the barrier layer 1062
Are formed under the same conditions, and the well layer 10 is formed thereon under the same conditions.
61 were formed in one layer. Thus, the MQW active layer 106 having a multiple quantum well structure was formed.

Subsequently, the temperature was maintained at 1100 ° C., N ₂ or H ₂ was 20 liter / min, NH ₃ was 10 liter / min, and TMG was 0.1 liter / min.
5 × 10 ⁻⁴ mol / min, Cp ₂ Mg is introduced at 2 × 10 ⁻⁷ mol / min, and a p-type second type guide layer 1072 made of magnesium (Mg) doped GaN and having a thickness of about 0.1 μm is formed. Was formed.
Further, N ₂ or H ₂ , NH ₃ , TMG, TMI, and Cp ₂ Mg are supplied to form a p-type first type of magnesium (Mg) doped In _0.05 Ga _0.95 N having a thickness of about 0.1 μm. A guide layer 1071 was formed.

Next, the temperature was maintained at 1100 ° C. and N ₂ or
H _{2 20} liter / min, NH ₃ 10 liter / min, TMA 5 × 1
0 ^-6 mol / min, 5 × 10 ^-5 mol / min of TMG and Cp ₂ M
g was introduced at 2 × 10 ⁻⁷ mol / min, and magnesium (Mg) was introduced.
Doped with about 100 nm thick magnesium
P-type cladding layer 10 made of (Mg) -doped Al _0.1 Ga _0.9 N
8 was formed.

Next, the temperature was maintained at 1100 ° C. and N ₂ or
H _{2 20} liter / min, NH ₃ 10 liter / min, TMG 5 × 1
0 ^-5 mol / min, was introduced Cp ₂ Mg at 2 × 10 ^-7 mol / min, magnesium (Mg) is doped, the thickness of about 20
A p-type contact layer 109 made of 0 nm magnesium (Mg) -doped GaN was formed.

Next, using an electron beam irradiation device, a p-type
Tact layer 109, p-type cladding layer 108 and p-type optical waveguide
The layer 107 was uniformly irradiated with an electron beam. Electron beam irradiation conditions
Is an acceleration voltage of about 10 kV, a sample current of 1 μA, and a beam shift.
Dynamic speed 0.2mm / sec, beam diameter 60μmφ, vacuum
Degree 5.0 × 10^-FiveTorr. This electron beam irradiation
Thus, the p-type contact layer 109 and the p-type clad layer 108
And the p-type optical waveguide layer 107 has a hole concentration of 5 × 1
0¹⁷/ Cm^Three, 5 × 10¹⁷/ Cm^Three, 5 × 10 ¹⁷/ Cm
^ThreeIt became. Thus, a multi-layer wafer is formed.
I was able to.

Next, an unillustrated SiO ₂ layer a is formed to a thickness of 200 nm on the p-type contact layer 109 by sputtering, and an unillustrated photoresist b is formed on the SiO ₂ layer a.
Was applied. Then, using an exposure device using ultraviolet light,
High carrier concentration n by photolithography process
^The photoresist b at the position corresponding to the region A (the exposed surface in FIGS. 2 and 3) having the deposition portion of the negative electrode 140 formed on the ⁺ layer 103 was removed.

However, in this photolithography step, in order to obtain the etched shape of the end portion of the resonator shown in FIG. 1B and Expression (4), FIG. 1A and Expressions (2) and (3) are used. The formation pattern of the resist mask shown in FIG.

Next, the photoresist b
Unillustrated SiO in region A_TwoLayer a is etched with hydrofluoric acid
And removed with a cleaning solution. Next, photoresist b and SiO_Twolayer
p-type contour at a site not covered by a (region A)
Layer 109, p-type cladding layer 108, p-type optical waveguide layer 1
07, MQW active layer 106, n-type optical waveguide layer 105, n-type
Cladding layer 104 and high carrier concentration n⁺One of layer 103
Part is vacuum degree 0.04 Torr, high frequency power 0.44 W /
cm ^Two, BCl_ThreeSupply gas at a rate of 10 ml / min and dry
Etched. After that, the area A is dried with Ar.
Etched. Resonance in these dry etching processes
The vessel remains in an I-shape as shown in FIGS. 1, 2 and 3.
Molded, high carrier concentration n⁺Negative electrode for layer 103
140 deposition surfaces were exposed. Then the SiO_TwoRemove layer a
did.

Next, rhodium or platinum (first metal layer having a thickness of about 0.3 μm), gold (second metal layer having a thickness of about 1.2 μm), titanium ( The third with a thickness of about 30mm
A positive electrode 120 was formed on the p-type contact layer 109 through successive application of a photoresist, a photolithography step, and an etching step. on the other hand,
For the high carrier concentration n ⁺ layer 103, a film thickness of about 175 °
Vanadium (V) layer and aluminum (A
l) layers were sequentially deposited to form a negative electrode 140.

Thereafter, the wafer processed as described above is scribed along the length direction (y-axis direction) of the laser resonator to form a scribe groove, and a die sink is formed in the x-axis direction parallel to the end face of the resonator. Then, a strip was obtained.

Next, in order to protect the end face of the resonator, SiO ₂ was deposited on the end face of the resonator by sputtering. Then, each strip was pressed by a roller, and separated into each element chip by using a scribe groove already formed along the y-axis direction. In this way, a resonator end face having a high degree of perpendicularity to the substrate 101 and a high degree of parallelism between the end faces, and having a high flatness of the surface and a high specularity was obtained.

As a result, the reflectance of light at the end face of the resonator was increased, and a high light confinement effect was obtained.
Also, by making the resonator end smaller than before,
Current constriction was effectively generated also near the end of the resonator, and the current path between the electrodes could be shortened.

By these actions, the threshold current and the calorific value could be reduced. The laser diode 100 thus obtained had a drive current of 1000 mA, an emission output of 10 mW, and an oscillation peak wavelength of 380 nm.

Incidentally, a protective film of SiO ₂ is formed on the end face of the above-mentioned resonator, and further, silicon oxide such as SiO ₂ , Si ₃ N ₄
May be formed on the end face by a dielectric such as silicon nitride or other TiO ₂ . By optimally designing the thickness of each of the multiple layers, the reflectance at the end face can be further improved.

As described above, by configuring the edge-emitting semiconductor laser diode, a laser diode with low power consumption and heat generation and high energy efficiency can be realized. Further, the effects of the present invention, such as good yield, small size, and high performance, can be obtained.

Although the structure of the active layer 106 in the above embodiment is a multiple quantum well (MQW) structure, the structure of the active layer 106 may be a single quantum well (SQW) structure.

In the above embodiment, the semiconductor layer 10
The crystal material from the second layer to the semiconductor layer 109 may be a gallium nitride-based compound semiconductor, and there is no particular limitation on the crystal material and composition ratio. These semiconductors have the general formula “Al _x Ga
Any binary, ternary or quaternary Group III nitride-based compound semiconductor represented by _y In _1-xy N (0 ≦ x, 0 ≦ y, x + y ≦ 1) or the like can be used.

Further, the active layer 106 and the clad layer 104,
When a double hetero junction is formed, the band gap of the active layer
The band gap may be selected so as to be smaller than the band gaps of 4, 108 and to match the lattice constant.

When an arbitrary quaternary group III nitride compound semiconductor is used, the band gap and the lattice constant can be changed independently, so that a double heterojunction having the same lattice constant in each layer can be formed. It becomes possible.

[0060] Further, p-type optical waveguide layer 107, p-type cladding layer 108, and a p-type contact layer 109 to reduce the resistance by electron beam irradiation, such a low-resistance treatment, thermal annealing, N ₂ plasma Heat treatment in a gas or laser irradiation may be performed.

In the above embodiment, the mask used in the etching step for the region A where the negative electrode 140 is formed has etching resistance to dry etching, such as metal and resist, in addition to SiO ₂ , and the underlying GaN-based semiconductor Any material that can be selectively etched or peeled off from the substrate can be used.

Although not particularly shown in the above embodiment, dry etching for shaping the end face of the resonator may be performed as shown below. (A) First, a photoresist is uniformly applied to the entire upper surface exposed at the upper part of the wafer, and a stripe having a stripe width in the y-axis direction and a length S (FIG. 2) in the x-axis direction is formed by photolithography. Region B (two regions where the y coordinate does not overlap with the resonator, and near both end surfaces of the resonator and y
By removing the photoresist in the area where the coordinates match (see FIGS. 4 and 6), a resist mask having a width corresponding to the length Y of the completed resonator (FIG. 2) is left along the x-axis.

(B) Next, the degree of vacuum is 1 mTorr and the high frequency power is 30
By supplying Cl ₂ gas at a rate of 5 ml / min at 0 W, dry etching is performed by reactive ion beam etching (RIBE) until the sapphire substrate 101 is exposed in the striped region B not covered with the resist mask. I do.

As described above, reactive ion beam etching
By performing (RIBE), it is possible to further improve the mirror accuracy of the end face of the resonator. The Makusu of such Enchingu for forming the resonator end faces (RIBE) process, other photoresist, has etching resistance to dry etching of SiO ₂ or the like, to the underlying electrodes, selectively etching Alternatively, a material that can be peeled off or the like can be used.

The acceptor impurity element added to the semiconductor may be a group II element or a group IV element in addition to zinc, and the donor impurity element may be a group IV element or a silicon element other than silicon.
Group VI elements can be used.

In the above embodiment, a sapphire substrate was used, but silicon (Si), SiC
, GaN, MgAl ₂ O ₄ or the like can be used. Although AlN is used for the buffer layer, AlGaN, GaN, InAlGaN, or the like can be used.

[Brief description of the drawings]

FIG. 1 is a plan view of a cavity end portion of an edge-emitting semiconductor laser illustrating the operation of the present invention.

FIG. 2 is a plan view of an edge-emitting semiconductor laser illustrating the effects of the present invention.

FIG. 3 shows an edge-emitting semiconductor laser 10 according to an embodiment of the present invention.
0 is a perspective view.

FIG. 4 shows a conventional edge emitting semiconductor laser 900.
FIG.

FIG. 5 shows a conventional edge emitting semiconductor laser 900.
FIG.

FIG. 6 shows a conventional edge emitting semiconductor laser 900.
FIG.

[Explanation of symbols]

REFERENCE SIGNS LIST 100 edge emitting semiconductor laser 101 sapphire substrate 102 buffer layer 103 high carrier concentration n ⁺ layer 104 n-type cladding layer 105 n-type optical waveguide layer 106 MQW active layer 107 p-type optical waveguide layer 108 p-type cladding layer 109 p-type contact layer 120 positive electrode 140 negative electrode

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Yamashita 1 Ochiai Nagahata, Kasuga-machi, Nishi-Kasugai-gun, Aichi Prefecture Inside Toyoda Gosei Co., Ltd. F term (reference) in Toyoda Gosei Co., Ltd. 5F041 AA03 CA04 CA05 CA34 CA40 CA46 CA87 CA92 CB05 5F073 AA22 AA45 AA55 AA73 AA74 AA86 CA07 CB05 CB22 DA05 DA35 EA23

Claims (3)

[Claims] 1. A plurality of semiconductor layers made of a group III nitride compound semiconductor are crystal-grown on a substrate, and a peripheral portion thereof is removed by etching while leaving a resonator portion, so that the semiconductor layer is removed from above in a crystal growth direction. A method of manufacturing an edge-emitting semiconductor laser in which the shape of a resonator viewed is an I-shaped mesa stripe type, comprising: a width D of an end face of the resonator in a resist mask formation pattern for the etching of the resonator. The width of the mesa stripe W parallel to the end face of the light emitting portion main body of the resonator is more than 2.0 to 2. A method for manufacturing an edge-emitting semiconductor laser, wherein the length is set to be twice as long. 2. A width d in a direction perpendicular to the end face of a left and right protruding portion having the I-shaped end face in the formation pattern is set to about 2.0 to 2.2 times the cutting length δ. The method for manufacturing an edge-emitting semiconductor laser according to claim 1, wherein: 3. The group III nitride compound semiconductor
3. The method according to claim 1, wherein Al _x Ga _y In _1-xy N (0 ≦ x, 0 ≦ y, x + y ≦ 1) is used.