JP3344633B2 - II-VI semiconductor laser and method of forming the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a II-VI group semiconductor laser and a method for forming the same.

[0002]

2. Description of the Related Art In a group III-V semiconductor laser,
For the purpose of reducing the oscillation threshold current and controlling the transverse mode,
A ridge type structure or a buried type structure is used. Of these, the embedded laser will be described in detail. The active layer is in the shape of a strip, and the reflecting mirrors formed by cleavage are arranged at both ends in the longitudinal direction of the strip, and the reflecting mirrors at both ends form a resonator. are doing. Both sides of the active layer along the axial direction of the resonator are embedded with a material having a lower refractive index and a wider band gap than the active layer, so that light is confined in the active layer. Further, the buried layer is an insulator or a pn junction layer having a configuration in which a reverse bias is applied when the laser is driven. As a result, no current flows through the buried layer, and the current is confined only to the active layer.

In order to produce the buried structure, a liquid phase growth method (LPE method) or a metal organic chemical vapor deposition method (MOCVD method) capable of selective growth is used.

On the other hand, II-VI semiconductor lasers do not realize a structure like the above-mentioned III-V semiconductor lasers, and at present have an elementary wind stripe structure. Briefly describing this laser having a wind stripe structure, a silicon oxide film or a polyimide insulating film is formed on the surface of a semiconductor substrate having a laser structure, a stripe-shaped window is opened in the insulating film, and current flows through this window. It has a flowing structure.

That is, the energized area is limited to the area where the window is opened. The longitudinal end face of this stripe is
It is a reflecting mirror formed by cleavage, and the reflecting mirror forms a resonator.

[0006]

By the way, in the above-mentioned structure, the effective light confinement and the effective light confinement in the region where the optical amplification occurs by energization (gain region: corresponding to the active layer of the III-V semiconductor laser). There is a problem that the carrier is not confined at all and the threshold value becomes high.

[0007] For this reason, at present, pulse oscillation at room temperature is only possible in II-VI semiconductor lasers. Further, since the threshold current is high, the operation of the element is unstable, and the life is short. Of course, since the both sides of the gain region are not surrounded by a material having a low refractive index, the transverse mode is not controlled at all.

As a result, it is impossible at this stage to realize a buried structure similar to a group III-V semiconductor with a group II-VI semiconductor due to insufficient crystal growth technology. Therefore, the conventional laser structure used in the III-V group cannot be applied to the II-VI group.

The present invention has been made in view of the above problems, and has been developed in view of the foregoing problems.
It is an object to provide a group I semiconductor laser and a method for forming the same.

[0010]

[0011]

[0012]

In order to achieve the object of the present onset to achieve the above purpose
The structure of the II-VI semiconductor laser according to the present invention is based on a semiconductor substrate having a (100) plane or a substrate surface slightly inclined from the (100) plane and having a high-resistance II-VI semiconductor on the outermost surface. And at least the active layer is formed of I
In a semiconductor laser having a double hetero structure or a separate confinement hetero structure composed of an I-VI semiconductor, the semiconductor substrate has a groove penetrating the high-resistance II-VI semiconductor layer, and the bottom surface of the groove is formed on the substrate surface. It is parallel and the side surface is a (111) plane or an inclined plane slightly inclined from the (111) plane, and a laser structure including at least a lower clad made of II-VI semiconductor, an active layer, and an upper clad is formed thereon. And at least a lower clad or an upper clad of the laser structure is disposed on the (111) plane of the groove.

In the method of forming a group II-VI semiconductor laser according to the present invention, the plane orientation is a (100) plane or a semiconductor substrate whose inclination is slightly inclined from the (100) plane, and the bottom surface is on the substrate surface. On a semiconductor substrate having a groove which is parallel and has a side surface which is a (111) plane or a slope slightly inclined from the (111) plane, a double hetero structure or a separate capacitor in which at least the active layer is made of a II-VI group semiconductor. In growing the structure of the fibration heterostructure semiconductor laser, a molecular beam epitaxial crystal growth method (MBE) is used.

The above method is characterized in that nitrogen is used as a p-type dopant and chlorine is used as an n-type dopant.

[0015]

[Action] molecular beam epitaxial crystal growth method by (MBE), the nitrogen-doped and chlorine-doped ZnSe and Z nS
_{When 0.07} Se _0.93 is simultaneously grown on the (111) plane and the (100) plane, even if the nitrogen-doped layer and the chlorine-doped layer grown on the (100) plane show low-resistance p-type and n-type, respectively. Any crystal grown on one (111) plane has a high resistance. Further, when a groove structure having a bottom surface parallel to the substrate surface and a side surface composed of the (111) surface is formed on the substrate to form a laser structure, the structure formed on the (100) surface and the (1) surface are formed.
11) The structure made on the surface has about 5
There is a 5 degree slope. Therefore, a layer having a lower refractive index than the active layer in the (111) plane structure is located on the lateral extension of the active layer. Therefore, the laser structure enables light confinement in the lateral direction of the active layer and current confinement in the lateral direction, thereby enabling low threshold oscillation and high temperature operation, and further, continuous oscillation at room temperature.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

(Example 1) Hereinafter, II-V according to the present invention will be described.
A first embodiment of the group I semiconductor laser will be described. FIG. 1 is a schematic view of a semiconductor laser using a p-type substrate according to a first embodiment of the present invention, and is a cross-sectional view of a laser resonator cut in a direction orthogonal to a light propagation direction.

In this embodiment, the direction perpendicular to the plane of the drawing is the [01 bar 1] direction. In FIG.
Type GaAs substrate 102 is a nitrogen-doped p-type ZnS _0.07 Se _0.93 optical confinement layer lattice-matched to the GaAs substrate
3 is a nitrogen-doped p-type ZnSe carrier confinement layer, 10
4 the multiple quantum well active layer made of a Zn _0.8 Cd _0.2 Se well layer 6 layers of ZnSe barrier layer, 105 an n-type ZnS
e carrier confinement layer, 106 is n-type ZnS _0.07 Se
_0.93 light confinement layer, 107 is a current blocking SiO ₂ insulating film, and 108 and 109 are titanium, platinum and gold deposited in this order, respectively.

Here, the layered structure of the layers 102 to 106 is a layered structure called a separate confinement hetero structure (SCH structure) which is a kind of the double-hetero structure described above. Light and carriers are separated and confined by the light confinement layer of the layer 106 and the carrier confinement layers of the layers 103 and 105, respectively.

Here, since the epitaxial growth layers on the regions A and B, which are the side surfaces of the GaAs groove, have grown on the (111) plane, they have high resistance. This is a nitrogen-doped II-V
This is based on the fact that the layer grown on the (111) plane has much higher resistance than the layer grown on the (100) plane in MBE growth of a group I semiconductor.

As described above, by arranging the structure of the semiconductor laser having the II-VI group compound semiconductor in the active layer on the semiconductor substrate having the inverted trapezoidal groove, the lateral light confinement (transverse mode control) is achieved. Current constriction is achieved simultaneously. That is, II grown on the (111) plane which is the slope of the groove.
Since the -VI compound semiconductor has a high resistance, current confinement is achieved. As shown in FIG. 1, a carrier confinement layer 1 having a lower refractive index than the active layer 104 is provided on a lateral extension of the active layer 104 formed at the bottom of the groove.
03 and the light confinement layer 102, light confinement in the lateral direction can be performed.

The fabrication method and characteristics of the device having the structure shown in FIG. 1 will be specifically described below.

Forming Grooves in Substrate The substrate used is a p-type GaAs substrate. 0.2 μm thick S
An iO ₂ thin film is formed. A 20 μm wide window of a band pattern is formed in the SiO ₂ film by photolithography. The direction of the groove is the crystal orientation [01 bar 1] of the GaAs substrate. Etching The GaAs substrate is etched to a depth of 8 μm by using methylated liquid crystal methyl. The SiO ₂ film is removed by etching with buffered hydrofluoric acid.

Crystal Growth As shown in FIG. 1, a nitrogen-doped p-ZnS layer having a thickness of 2 μm was formed on the processing substrate formed by the above-described method by using MBE.
_0.07 Se _0.93 (layer 102: carrier concentration 5 × 10 ¹⁷ c
m ⁻³ ), 1 μm thick nitrogen-doped p-ZnSe (layer 10
3: Multiple quantum well structure 1 consisting of a 10 nm thick non-doped ZnS _0.8 Cd _0.2 Se well layer and a 10 nm thick non-doped ZnSe barrier layer with a carrier concentration of 5 × 10 ¹⁷ cm ⁻³ )
04: (number of well layers 6), chlorine-doped nZ having a thickness of 1 μm
nSe (layer 105: carrier concentration 1 × 10 ¹⁸ cm ⁻³ ), chlorine-doped n-ZnS _0.07 Se _0.93 (layer 1) having a thickness of 1.5 μm
06: Carrier concentration of 1 × 10 ¹⁸ cm ⁻³ ) at a temperature of 300 ° C.
Grown in. However, the films grown on the regions A and B have high resistance.

Here, nitrogen-doped Z
An experimental example in which the acceptor concentration of the nSe thin film is changed will be described.
When a nitrogen-doped ZnSe thin film was simultaneously MBE-grown on the (100) substrate, the (111) B substrate, and the (111) A substrate, those grown on the (100) substrate were grown at room temperature for 5.
While showing an acceptor concentration of 8 × 10 ¹⁷ cm ⁻³ , (1
11) Those grown on the B substrate had such high resistance that the conduction type could not be discriminated by the CV method measured by forming electrodes on the substrate and the grown crystal surface.

A 0.2 μm- thick Si film is formed on the entire surface of the substrate on which the current blocking layer is formed by high frequency sputtering.
An O ₂ thin film is formed. A window of a 10-μm wide band-shaped pattern is formed in the SiO ₂ film by photolithography. The center in the width direction of this strip pattern is aligned with the center in the width direction of the groove formed on the substrate surface. Of course, the direction of the groove is the crystal orientation [01 bar 1] of the GaAs substrate.

The substrate side is polished using methyl bromide on the thinning cloth of the crystal substrate, and the thickness is reduced to 7 mm.
0 μm.

Electrode formation On the epitaxial growth layer side and the substrate side, a 30 nm thick titanium, 50 nm
The electrodes 108 and 109 are respectively formed by depositing platinum of 200 nm and gold of 200 nm in this order. Thereafter, flash annealing is performed in a hydrogen atmosphere at 200 ° C. for 60 seconds to improve the adhesion between the electrode metal and the semiconductor.

The laser chip is cut out from the wafer by chipping and cleavage.

Device Characteristics FIG. 2 shows the light output-injection current characteristics when the device having the structure shown in FIG. 1 is mounted on a diamond heat sink by junction down using a gold-tin eutectic alloy. Here, the resonator length was 1 mm, the pulse width was 1 μs, the repetition was 1 kHz, and the threshold current density at room temperature was 490 A / cm ² . The oscillation wavelength was 510 nm, and the external differential quantum efficiency was 39% per end face. When the near-field image was observed, oscillation occurred in a single transverse mode in the range shown in FIG.

When the characteristics of a 20 μm wide oxide film windstrip type laser diode fabricated using crystals grown on the (100) plane simultaneously with the present device were examined, the threshold current density under the same measurement conditions was 1 0.1 kA / cm ^2, which is more than twice as high as that of the device of the present invention. Also,
The external differential quantum efficiency was 12% per end face, which was 1/3 or less as compared with the device of the present invention. Immediately after the oscillation, the transverse mode became multi-mode.

As described above, an example in which a p-GaAs substrate is used
However, an n-GaAs substrate may be used. This place
The conduction type of the semiconductor that constitutes the LD structure is a p-type substrate.
The opposite is the case. Also, when using an n-type substrate
The metal electrode for the p-type semiconductor layer is p-type ZnS_0.07Se _0.93
In this case, the current-voltage characteristics
A voltage barrier of 20 V to 30 V occurs. Reduce this barrier
For this purpose, a cap layer such as ZnTe may be formed.
No. In the case where this cap layer is formed, it is shown in the embodiment.
Current blocking SiO_TwoInstead of forming the insulating film 107
Then, even if the cap layer other than the current injection region is removed,
Current constriction can be achieved.

Although GaAs is used here as a substrate, InGaAs may be used as long as it can grow a laser structure.
It is clear that other substrates such as As and InGaP may be used. Further, ZnS _0.07 Se _0.93 is formed on the layers 102 and 106.
Layer was used, but matched to GaAs, ZnS _0.87 Se _0.93
Other crystals may be used as long as they are compound semiconductors having a refractive index equal to or lower than that and having a forbidden band width wider than the oscillation wavelength energy. For example, Zn _0.37 Cd
_0.63 S or the like, or a superlattice layer of ZnSe and ZnSSe can be used.

In this embodiment, the axial direction of the laser resonator is set to [01 bar 1]. However, it is sufficient that the groove as shown in the embodiment can be formed in a normal mesa shape in other directions. ,it is obvious. Further, the side wall of the groove formed in the substrate may not be the (111) plane but may be in the vicinity thereof.

(Embodiment 2) Next, II according to the second embodiment of the present invention.
An example of a -VI group semiconductor laser will be described. FIG. 3 is a schematic view of a semiconductor laser using a p-type substrate according to a second embodiment of the present invention, and is a cross-sectional view of a laser resonator cut in a direction orthogonal to a light propagation direction.

Here, in this embodiment, the direction perpendicular to the paper surface is the [01 bar 1] direction. In FIG. 3, reference numeral 1 denotes a p-type G
aAs substrate, 2 is a nitrogen-doped p-type ZnS _0.07 Se _0.93 optical confinement layer lattice-matched to a GaAs substrate, 3 is a nitrogen-doped p-type ZnSe carrier confinement layer, and 4 is a 6-layer Zn
_{The 0.8} Cd _0.2 Se well layer is a multiple quantum well active layer comprising a ZnSe barrier layer, 5 is an n-type ZnSe carrier confinement layer, 6 is an n-type ZnS _0.07 Se _0.93 optical confinement layer, and 7 is titanium, platinum and gold in this order. A vapor-deposited n-side ohmic electrode 8 is a gold electrode via chromium.

[0037] Here, the laminated structure of the layer 2 to layer 6 is adapted to the laminated structure called a separate configuration file placement heterostructure is a kind of terrorism structures to double that previously described (SCH structure), a layer 2 And the light confinement layer of the layer 6 and the carrier confinement layers of the layers 3 and 5 separate and confine light and carriers, respectively. Reference numerals 9 to 13
And 15 to 19 illustrate the layers grown on the (111) plane 20 and the (100) plane 21 at the same time as the MBE growth of the layer 2 to the layer 6, each corresponding layer having a growth interface 22, At 23.

However, the nitrogen-doped ZnSe layer 10
And the nitrogen-doped ZnS _0.07 Se _0.93 layer 9 are both (11
1) High resistance since grown on the surface. This is because (1) in MBE growth of a nitrogen-doped II-VI semiconductor.
11) The fact that the layer grown on the plane has much higher resistance than the layer grown on the (100) plane at the same time.

The layers 12 and 13 also have high resistance.
is there. Prior to MBE growth of the SCH structure,
E or MOCVD on one GaAs substrate
Zn processed to expose the (111) plane 21
S_0.07Se_0.93Layer. This layer is undoped and highly
Resistance, so that even if a forward bias is applied to the device,
No current flows in each of layers 15 to 17 grown on the substrate.
Also, ZnS_0.07Se _0.93Lateral light confinement by layer 9
Layer 1 on its lateral extension, even if the
4, or layer 15 or layer 16 is a light confinement layer
Act.

Here, a ZnS _0.07 Se _0.93 layer is used as the layer 9, but a compound semiconductor that matches GaAs and has a refractive index equal to or lower than that of ZnS _0.07 Se _0.93, and has a forbidden energy wider than the oscillation wavelength energy. Any material having a band width may be used. For example, ZnS _0.37
Cd _0.63 S may be used. Also, ZnSe and ZnSSe
May be used.

Hereinafter, a method of manufacturing an element having a structure shown in FIG. 3 using a p-type substrate and its characteristics will be specifically described.

Substrate formation The substrate used was a MBE on a (100) GaAs substrate.
Alternatively, a non-doped ZnS _0.07 Se _0.93 layer having a thickness of 4 μm grown by MOCVD was processed as shown in FIG. In the figure, a depth direction L is a direction to be a longitudinal direction of the resonator in the future, a front surface is a cross section thereof, and reference numeral 44 denotes G.
The aAs substrate 45 shows a high resistance layer. Moreover, processing was carried out by a wet etching method photolithography and ZnS _0.07 Se _0.93 layer, the ZnS _0.07
An etching solution is used which provides a mirror surface to the Se _0.93 layer and whose side surface formed by etching becomes an inclined surface such as a (111) surface. Here, as an etchant,
A bromomethanol solution was used. The width of the side facing the bottom surface of the groove in the figure is 20 μm.

Crystal growth As shown in FIG. 3, a 2 μm thick nitrogen-doped p-ZnS
_0.07 Se _0.93 (Carrier concentration 5 × 10 ^{17 in} layers 2 and 15)
cm ⁻³ , layer 9 has high resistance), 1 μm thick nitrogen-doped pZ
nSe (carrier concentration of 5 × 10 ¹⁷ cm ⁻³ in layers 3 and 16;
The layer 10 has a high resistance), and a non-doped ZnS _{0.8 having} a thickness of 10 nm.
Cd _0.2 Se well layer and 10 nm thick non-doped ZnSe
Multiple quantum well structures 4, 11, 17 (the number of well layers 6) composed of barrier layers, chlorine-doped n-ZnSe having a thickness of 1 μm (layer 5, layer 18: carrier concentration 1 × 10 ¹⁸ cm ⁻³ , layer 12: high) Resistance), chlorine-doped n-ZnS _0.07 Se with a thickness of 1.5 μm
_0.93 (layer 6, layer 19: carrier concentration of 1 × 10 ¹⁸ cm ⁻³ , layer 13: high resistance) was grown at a temperature of 300 ° C.

An experimental example in which the acceptor concentration of a nitrogen-doped ZnSe thin film changes depending on the substrate plane orientation will be described. (100)
Nitrogen doped ZnS on the substrate and (111) B substrate simultaneously
When e-thin films were grown by MBE, those grown on the (100) substrate showed an acceptor concentration of 5.8 × 10 ¹⁷ cm ^-3 at room temperature, whereas those grown on the (111) B substrate were: An electrode was formed on the substrate and the surface of the grown crystal, and the measured C
The resistance was so high that the conduction type could not be determined by the -V method. Further, the (111) A substrate, the (111) A surface, and the (1)
11) The growth layer also had high resistance when the off-substrate slightly inclined from the B-plane was used.

When a p-type substrate is used as shown in FIG. 3, on the crystal growth side, 30 nm thick titanium, 50 nm platinum and 200 nm
nm gold is deposited by sputtering in this order, and titanium / platinum /
An electrode 7 made of gold is formed. On the substrate side, chromium with a thickness of 40 nm and gold with a thickness of 0.5 μm are successively deposited,
An electrode 8 made of chromium / gold is formed. Thereafter, flash annealing is performed in a hydrogen atmosphere at 200 ° C. for 60 seconds to improve the adhesion between the electrode metal and the semiconductor. Finally, the laser chip is cut out from the wafer by cleavage.

Device Characteristics FIG. 5 shows light output-injection current characteristics when the device having the structure shown in FIG. 3 is mounted on a diamond heat sink by using a gold-tin eutectic alloy at a junction down. Here, the resonator length was 1 mm, the pulse width was 1 μs, the repetition was 1 kHz, and the threshold current density at room temperature was 490 A / cm ² . The oscillation wavelength was 510 nm, and the external differential quantum efficiency was 39% per end face. When the near-field image was observed, oscillation occurred in the single transverse mode in the range shown in FIG.

The characteristics of a 20 μm wide oxide film windstrip type laser diode fabricated using a crystal grown on the (100) plane simultaneously with this device were examined. The threshold current density under the same measurement conditions was 1 0.1 kA / cm ^2, which is more than twice as high as that of the device of the present invention. Also,
The external differential quantum efficiency was 12% per end face, which was 1/3 or less as compared with the device of the present invention. Immediately after the oscillation, the transverse mode became multi-mode.

(Embodiment 3) In the first embodiment described above, an element formed on a p-type substrate has been described. However, in the present invention, as shown in FIG. 6, an element can be manufactured even when an n-type substrate is used. . In this case, as shown in FIG. 6, the laser structure may be a structure in which a p-substrate is used and a structure in which pn is inverted. At this time, gold having a thickness of 0.2 μm was vapor-deposited on the entire surface as the p-electrode 30 by an electron beam sputter vapor deposition method.
And platinum having a thickness of 0.5 μm were continuously deposited. still,
In the figure, 32 is an n-type ZnS _0.07 Se _0.93 optical confinement layer on the (111) plane, 33 is an n-type ZnSe carrier confinement layer on the (111) plane, and 34 is Zn _0.8 Cd _0.2 S on the (111) plane.
e / ZnSe multiple quantum well, 35 is a high resistance nitrogen doped ZnSe layer on the (111) plane, 36 is a high resistance nitrogen doped ZnS _0.07 Se _0.93 layer on the (111) plane, and 37 is a high resistance ZnS
_0.07 Se _0.93 layer, 38 is n-type ZnS _0.07 Se _0.93 layer, 3
9 is an n-type ZnSe layer, 40 is Zn _0.8 Cd _0.2 Se / Z
nSe multiple quantum well; 41, nitrogen-doped ZnSe layer;
Reference _numeral 2 denotes a nitrogen-doped ZnS _0.07 Se _0.93 layer.

In the above description, G is used as the substrate.
Although aAs was used, it is clear that other substrates such as InGaAs and InGaP may be used as long as they can grow a laser structure.

Further, in this embodiment, the axial direction of the laser resonator is set to [01 bar 1], but it is sufficient that the groove as shown in the embodiment can be formed in a normal mesa shape in other directions. ,it is obvious.

[0051]

As described above, in the present invention, by growing a laser structure on the (100) plane sandwiched between the (111) planes, the crystal grown on the (111) plane has a high resistance. This layer acts as a current confinement layer and further acts as a light confinement layer on the side surface of the stripe-shaped active layer. Therefore, the conventional MBE technology can be used to easily achieve low threshold current density, high external quantum efficiency, and transverse mode. A laser diode having excellent stability can be manufactured.

On the other hand, when forming a laser structure having a II-VI group semiconductor in an active layer in a groove structure having a (111) plane on a side surface and a (100) plane on a bottom surface, (1)
11) On the surface, a layer of a high resistance II-VI group semiconductor having the same composition as the cladding layer is placed. For this reason,
The current is confined by the high resistance layer on the (111) plane, and the refractive index of the layer is lower than that of the active layer formed on the (100) plane, so that light is efficiently confined in the active layer. Since current confinement and light confinement are efficiently performed, the present invention has an effect that a high-performance II-VI group semiconductor laser can be easily obtained by using the present invention.

Further, MB containing chlorine and nitrogen as dopants
When a laser structure having an II-VI group semiconductor as an active layer is grown in a groove structure having a (111) plane on a side surface and a (100) plane on a bottom surface by the E method, a layer grown on the (111) plane is obtained. Automatically becomes a high-resistance layer, and has the effect that the above structure is realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of a structure of a semiconductor laser according to a first embodiment of the present invention using a p-type substrate, which is perpendicular to a light propagation direction.

FIG. 2 is an example of characteristics of the semiconductor laser of the present invention.

FIG. 3 is a sectional view of a structure of a semiconductor laser according to a second embodiment of the present invention using a p-type substrate, which is perpendicular to a light propagation direction.

FIG. 4 is a perspective view of a substrate processed for MBE growth of the laser structure according to the present invention.

FIG. 5 is a graph showing characteristics of the semiconductor laser of the present invention.

FIG. 6 is a schematic sectional view of a semiconductor laser according to a third embodiment of the present invention using an n-type substrate.

[Explanation of symbols]

_Reference Signs _List 101 p-type GaAs substrate 102 nitrogen-doped p-type ZnS _0.07 Se _0.93 optical confinement layer 103 nitrogen-doped p-type ZnSe carrier confinement layer 104 Zn _0.8 Cd _0.2 Se / ZnSe multiple quantum well active layer 105 n-type ZnSe carrier confinement layer 106 n-type ZnS _0.07 Se _0.93 Optical confinement layer 107 SiO ₂ insulating film for current blocking 108 Titanium / platinum / gold electrode 109 Titanium / platinum / gold electrode A (111) plane B (111) plane 1 p-type GaAs substrate 2 nitrogen-doped p-type ZnS _0.07 Se _0.93 light confinement layer 3 nitrogen-doped p-type ZnSe carrier confinement layer 4 Zn _0.8 Cd _0.2 Se / ZnSe multiple quantum well active layer 5 n-type ZnSe carrier confinement layer 6 n-type ZnS _0.07 Se _0.93 light confinement layer 7 titanium / platinum / gold Electrode 8 Chromium / gold electrode 9 High resistance nitrogen on (111) surface -Loop ZnS _0.07 Se
_0.93 Optical confinement layer 10 High-resistance nitrogen-doped ZnSe carrier confinement layer on (111) plane 11 Zn _0.8 Cd _0.2 Se / ZnSe on (111) plane
Multiple quantum well 12 n-type ZnSe layer on (111) plane 13 n-type ZnS _0.07 Se _0.93 layer on (111) plane 14 High resistance ZnS _0.07 Se _0.93 layer 15 nitrogen-doped ZnS _0.07 Se _0.93 layer 16 nitrogen-doped ZnSe layer 17 Zn _0.8 Cd _0.2 Se / ZnSe multiple quantum well 18 n-type ZnSe layer 19 n-type ZnS _0.07 Se _0.93 layer 20 ZnS _0.07 Se _0.93 (111) layer 21 ZnS _0.07 Se _0.93 (100) layer 22 Growth interface 1 23 Growth interface 2 24 n-type GaAs substrate 25 n-type ZnS _0.07 Se _0.93 optical confinement layer 26 n-type ZnSe carrier confinement layer 27 Zn _0.8 Cd _0.2 Se / ZnSe multiple quantum well active layer 28 nitrogen-doped p-type ZnSe carrier confinement layer 29 nitrogen-doped p-type ZnS _0.07 Se _0.93 optical confinement layer 30 gold electrode 31 of titanium / platinum / gold electrode 32 (1 1) surface on the n-type ZnS _0.07 Se _0.93 optical confinement layer 33 (111) plane on the n-type ZnSe carrier confinement layer 34 (111) plane on the Zn _0.8 Cd _0.2 Se / ZnSe
Multiple quantum well 35 High resistance nitrogen-doped ZnSe layer on (111) plane 36 High resistance nitrogen-doped ZnS _0.07 Se on (111) plane
_0.93 layer 37 High resistance ZnS _0.07 Se _0.93 layer 38 n-type ZnS _0.07 Se _0.93 layer 39 n-type ZnSe layer 40 Zn _0.8 Cd _0.2 Se / ZnSe multiple quantum well 41 nitrogen-doped ZnSe layer 42 nitrogen-doped ZnS _0.07 Se _0.93 layer 44 GaAs substrate 45 High resistance ZnS _0.07 Se _0.93 layer L Resonator direction

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-15088 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01S 5/00-5/50

Claims (3)

(57) [Claims] 1. A (100) plane or (100) plane orientation
A double hetero structure or a separate configuration having a substrate surface slightly inclined from the surface and formed on a semiconductor substrate comprising a high-resistance II-VI semiconductor layer on the outermost surface and at least an active layer comprising a II-VI semiconductor layer In a semiconductor laser having a heterostructure, the semiconductor substrate has a groove penetrating the high-resistance II-VI semiconductor layer, a bottom surface of the groove is parallel to the substrate surface, and
The side surface is a (111) plane or an inclined plane slightly inclined from the (111) plane, on which a laser structure including at least a lower clad made of II-VI semiconductor, an active layer, and an upper clad is arranged, and the groove is formed. A II-VI semiconductor laser, wherein at least a lower cladding or an upper cladding of the laser structure is disposed on the (111) plane. 2. The plane orientation is (100) plane or (100) plane.
The semiconductor substrate is slightly inclined from the surface, the bottom surface is parallel to the substrate surface, and the side surface is the (111) plane or the (11) plane.
1) In growing a double hetero structure or a separate confection hetero structure semiconductor laser in which at least the active layer is made of a II-VI group semiconductor on a semiconductor substrate having a groove that is a slope slightly inclined from the surface, A method for forming a group II-VI semiconductor laser, comprising using a line epitaxial crystal growth method (MBE). 3. A nitrogen, a method of forming a Group II-VI semiconductor laser according to claim 2 which comprises using chlorine as an n-type dopant as a p-type dopant.