JP3395194B2 - Surface emitting semiconductor laser - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface emitting semiconductor laser which oscillates laser light in a direction perpendicular to a substrate and a method for manufacturing the same.

[0002]

2. Description of the Related Art A surface emitting laser having a resonator in a direction perpendicular to a substrate is described in Proceedings of the 50th Academic Meeting of the Society of Applied Physics, 3rd volume, p. 9029a-ZG-7 (issued September 27, 1989). According to this conventional technique, as shown in FIG. 12, first, (602) n-type GaA
(603) n-type AlGaAs / AlAs multilayer film, (604) n-type AlGaAs cladding layer, (60)
5) p-type GaAs active layer, (606) p-type AlGaAs
The clad layer is formed by sequentially growing it. After that, etching is performed leaving the columnar region, and (607) p-type,
(608) n-type, (609) p-type, (610) p-type are formed in this order by liquid phase growth of AlGaAs, and the periphery of the cylindrical region is buried. After that, (610) p-type AlGaA
A surface emitting semiconductor laser is formed by vapor-depositing a (611) dielectric multilayer film on the s cap layer to form a (612) p-type ohmic electrode and a (601) n-type ohmic electrode. As described above, in the conventional technique, the pn junction made of (607-608) is provided in the buried layer as a means for preventing the current from flowing to the portion other than the active layer.

[0003]

However, it is difficult to obtain sufficient current confinement in this pn junction, and the reactive current cannot be completely suppressed. Therefore, in the conventional technique, it is difficult to drive the continuous oscillation at room temperature due to the heat generation of the element, which is not practical. Therefore, suppression of the reactive current is an important issue in the surface emitting semiconductor laser.

Further, when the buried layer has a multi-layer structure for forming a pn junction as in the conventional case, the buried layer p-
Regarding the position of the n-interface, it is necessary to consider the interface position of each growth layer left in a cylindrical shape. Therefore, it is difficult to control the film thickness of each embedded growth layer having a multilayer structure, and it is extremely difficult to manufacture a surface-emitting type semiconductor laser with good reproducibility.

Further, when a buried layer is formed around a cylinder by liquid phase growth as in the prior art, there is a high risk that the cylinder part will be broken, the yield is poor, and the improvement of characteristics is restricted due to structural reasons. I will end up.

Further, the prior art has various problems when applied to devices such as laser printers.

In a laser printer or the like, when a light-emitting spot size of a light-emitting source (semiconductor laser or the like) used as a light source is as large as several tens of μm and a light-emitting element having a strong light emission intensity is used, the optical system is simplified and the optical path length is shortened. More freedom in designing things you can do.

Surface-emitting type semiconductor laser 1 using conventional technology
In the case of an element, since the entire optical resonator is embedded with a material having a lower refractive index than the resonator, light is mainly guided in the vertical direction, and the light emission spot in the fundamental oscillation mode resonates in the horizontal direction. Even if the shape of the container is changed, point emission with a diameter of about 2 μm will occur.

Therefore, it is attempted to bring these light emitting points close to each other by about 2 μm to increase the spot size with a plurality of light sources.
Embedding by E growth is extremely difficult in terms of reproducibility and yield, and is difficult to manufacture. Moreover, even if the resonator is embedded by approaching it to a distance of several μm, there is little light leakage in the lateral direction, so that one spot cannot be formed.

Further, it is necessary to synchronize the phases of the laser beams of the plurality of spots in order to increase the light emission intensity by forming a beam having one luminous flux from the plurality of light emission spots. In the prior art, it is difficult to manufacture the laser beams in close proximity to each other so as to influence each other in order to synchronize the phases of the laser beams.

The present invention solves such a problem. An object of the present invention is to improve the material of the burying layer so that it has a structure capable of complete current confinement and can be manufactured extremely easily. An object of the present invention is to provide a highly efficient surface emitting semiconductor laser and a manufacturing method thereof.

Another object of the present invention is to provide a surface-emitting type semiconductor laser capable of bringing a plurality of light emitting parts close to each other and synchronizing the phase of laser light from each light emitting part, and a method for manufacturing the same. It is in.

Still another object of the present invention is to use a phase-synchronized laser beam from a plurality of light emitting sections as a beam of light having a single luminous flux, a large emission spot, and a narrow emission angle of the laser beam. A laser and a manufacturing method thereof are provided.

[0014]

A first surface-emitting type semiconductor laser of the present invention includes a semiconductor substrate, a lower reflecting mirror formed above the semiconductor substrate, and a lower reflecting mirror formed above the lower reflecting mirror. An optical resonator including a lower clad layer, an active layer formed above the lower clad layer, and an upper clad layer formed above the active layer and having a columnar portion in the upper part, and above the columnar portion. An upper reflection mirror formed on the optical resonator, and a separation groove that divides the columnar portion and does not reach the active layer is formed in the optical resonator. It is characterized in that it is formed on the groove.

In the above surface emitting semiconductor laser, it is preferable that the width of the separation groove is 5 μm or less. In addition, the plurality of light emitting units have a cross-sectional shape parallel to the semiconductor substrate, which is either a circle or a regular polygon, and a diameter of the circle or a diagonal line of the regular polygon is less than 10 μm. Preferably there is. Further, the thickness of the contact layer is preferably 3.0 μm or less. It is preferable that each of the columnar portions has a region serving as a light emitting portion. Around the column
It is preferable that an epitaxial layer of a II-VI group compound semiconductor is formed.

Since the II-VI group compound semiconductor epitaxial layer has a high resistance, leakage of the injection current into the buried layer formed of this high resistance layer does not occur, and extremely effective current confinement is achieved. Since the reactive current can be reduced, the threshold current can be reduced. As a result, it is possible to realize a surface-emitting type semiconductor laser with less heat generation, and to provide a highly practical surface-emitting type semiconductor laser capable of continuous oscillation at room temperature. Further, since this buried layer does not have a multi-layer structure, it can be easily formed and the reproducibility is also good. In addition, II-
The Group VI compound semiconductor epitaxial layer can be formed by a method other than liquid phase growth, for example, vapor phase growth, and columnar semiconductor layers can be formed with good yield. Moreover, by using vapor phase growth or the like, the buried layer can be reliably formed even if the buried width is narrow, so that there is an effect that a plurality of columnar semiconductor layers can be arranged close to each other.

Like the fifth surface-emitting type semiconductor laser of the present invention, when the thickness of the semiconductor contact layer on the light emitting side of the optical resonator is 3.0 μm or less, light absorption in the contact layer is reduced. it can.

As in the third surface-emitting type semiconductor laser of the present invention, if the cross section of the columnar semiconductor layer parallel to the semiconductor substrate is either a circle or a regular polygon, a clean circular spot beam can be obtained. . As in the fourth surface-emitting type semiconductor laser of the present invention, either the diameter of the cross section of the columnar semiconductor layer parallel to the semiconductor substrate or the length of the diagonal line is 10
When it is less than μm, the NFP mode becomes the 0th-order basic mode.

[0019]

[0020]

To increase the emission spot, the separation groove is filled with a II-VI group compound semiconductor epitaxial layer which is transparent to the wavelength of the emitted laser light. Further, the light emitting side reflecting mirror is formed over a region facing the II-VI group compound semiconductor epitaxial layer embedded in each of the plurality of columnar end faces and the separation groove. This way
The region sandwiched by the columnar light emitting parts also has a vertical resonator structure,
The light leaked into the area also effectively contributes to the laser oscillation and the light emission spot spreads. Further, since the phase-synchronized laser lights are superposed, the light output increases and the emission angle also decreases. Ga which is generally used as a semiconductor layer of a resonator
In the case of As laser, it is transparent to the wavelength of the laser light.
As the II-VI group compound semiconductor epitaxial layer, Zn
It can be composed of any one of Se, ZnS, ZnSSe, ZnCdS, and CdSSe. When the separation groove is a groove that is perpendicular to the semiconductor substrate, the light that obliquely enters the separation groove can be totally reflected by utilizing the refractive index step, and the light confinement effect becomes large. If the width of the cross section of the separation groove parallel to the semiconductor substrate is 0.5 μm or more and less than 10 μm, the order of the oscillation transverse mode measured from the NFP is the 0th fundamental mode.

[0022]

[0023]

[0024]

[0025]

1 is a perspective view showing a cross section of a light emitting portion of a semiconductor laser (100) in an embodiment of the present invention, and FIG. 2 is a cross sectional view showing a manufacturing process of a semiconductor laser in an embodiment of the present invention.

(102) n-type GaAs substrate, (10
3) An n-type GaAs buffer layer is formed, and n-type Al _0.7 G
30 pairs of (104) distributed reflection type multilayer film mirrors each having a reflectance of 98% or more with respect to light having a wavelength of about 870 nm are formed from an a _0.3 As layer and an n-type Al _0.1 Ga _0.9 As layer. Further, (105) n-type Al _0.4 Ga _0.6 As cladding layer, (106) p-type GaAs active layer, (107) p
Type Al _0.4 Ga _0.6 As clad layer, (108) p-type A
l _0.1 Ga _0.9 As contact layer are successively epitaxially grown by MOCVD (FIG. 2 (a)). At this time, for example, the growth temperature is 700 ° C. and the growth pressure is 150 Torr.
Then, TMGa (trimethylgallium), T
Using an organic metal such as MAl (trimethylaluminum),
AsH ₃ was used as the group V raw material, H ₂ Se was used as the n-type dopant, and DEZn (diethyl zinc) was used as the p-type dopant.

After the growth, the surface (11
2) After forming the SiO ₂ layer, a reactive ion beam etching method (hereinafter referred to as RIBE method) is used to perform (11
3) The (107) p-type Al _0.4 Ga _0.6 As cladding layer is etched halfway, leaving the columnar light-emitting portion covered with the hard bake resist (FIG. 2B). On this occasion,
Using a mixed gas of chlorine and argon as the etching gas,
The gas pressure was 1 × 10 ⁻³ Torr, and the extraction voltage was 400V. Here, the _reason why the (107) p-type Al _0.4 Ga _0.6 As clad layer is etched only halfway is that the horizontal injection carrier and light confinement in the active layer are made into a rib waveguide type refractive index waveguide structure. This is because.

(113) After removing the resist,
A (109) ZnS _0.06 Se _0.94 layer lattice-matched with GaAs is buried and grown by the MBE method or MOCVD method (FIG. 2C).

Further, 4 pairs of (111) SiO 2 are formed on the surface.
_{A 2} / α-Si dielectric multilayer film is formed by electron beam vapor deposition and removed by wet etching, leaving a region slightly smaller than the diameter of the light emitting portion (FIG. 2D). Wavelength 870nm
The reflectance of the dielectric multilayer film is 94%.

Then, a (110) p-type ohmic electrode is vapor-deposited on the surface other than the (111) dielectric multilayer film, and a (101) n-type ohmic electrode is vapor-deposited on the substrate side at 420 ° C. in an N ₂ atmosphere. By alloying, a (100) surface emitting semiconductor laser is completed (FIG. 2E).

In the surface emitting semiconductor laser of this example thus produced, the ZnS _0.06 Se _0.94 layer used for burying was one layer.
Since it has a resistance of GΩ or more and leakage of the injection current into the buried layer does not occur, extremely effective current confinement is achieved.
Further, since the embedded layer does not need to have a multi-layer structure, it can be easily grown and the reproducibility between batches is high. Further, the rib waveguide structure using a ZnS _0.06 Se _0.94 layer having a sufficiently smaller refractive index than GaAs realizes more effective light confinement.

FIG. 3 is a diagram showing the relationship between the drive current and the oscillation light output of the surface emitting semiconductor laser according to the embodiment of the present invention. Continuous oscillation was achieved at room temperature, and an extremely low value of 1 mA was obtained. The external differential quantum efficiency is also high, and the suppression of reactive current contributes to the improvement of laser characteristics.

In the cross-sectional shape of the columnar portion of the surface emitting semiconductor laser according to the embodiment of the present invention, if the shape is a circle or a regular polygon such as a regular quadrangle or a regular octagon, the spot beam becomes a clean circle, but otherwise. The rectangular shape, the trapezoidal shape, or the like has an elliptical shape or a multimode beam shape, which is not preferable for application to a device.

[0034]

[Table 1] Table 1 shows the relationship between the near-field image and the diameter length of the cross section of the cylindrical portion of the surface emitting semiconductor laser of the example of the present invention. 1
It oscillates in the fundamental mode below 0 μm, but above that,
It oscillated in the first and higher modes.

The thickness of the contact layer of the surface emitting semiconductor laser of the embodiment of the present invention is preferably 3.0 μm or less. This is because light absorption in the contact layer can be reduced. More preferably, 0.3 μm or less is optimal, the device resistance is low, and the external differential quantum efficiency is high.

FIG. 4 is a perspective view showing a cross section of a light emitting portion of a semiconductor laser (200) according to another embodiment of the present invention.
Is a semiconductor laser (200) according to another embodiment of the present invention.
FIG. 6 is a cross-sectional view showing the manufacturing process of.

(202) n-type GaAs substrate, (20
3) An n-type GaAs buffer layer is formed and is composed of an n-type AlAs layer and an n-type Al _0.1 Ga _0.9 As layer and has a wavelength of 870 nm.
30 pairs of (204) distributed reflection type multilayer film mirrors having a reflectance of 98% or more with respect to nearby light are formed. Further, a (205) n-type Al _0.4 Ga _0.6 As clad layer,
(206) p-type GaAs active layer, (207) p-type Al
_0.4 Ga _0.6 As clad layer, (208) p-type Al _0.1
A Ga _0.9 As contact layer is sequentially epitaxially grown by MOCVD (FIG. 5A). At this time, for example, the growth temperature is 700 ° C., the growth pressure is 150 Torr, and III
TMGa (trimethylgallium) and TMAl as group materials
An organic metal (trimethylaluminum) was used, AsH ₃ was used as a group V raw material, H ₂ Se was used as an n-type dopant, and DEZn (diethyl zinc) was used as a p-type dopant. After growth,
After forming (212) SiO ₂ on the surface by thermal CVD method, reactive ion beam etching method (hereinafter, RIBE
(213) n-type Al by leaving (213) a cylindrical light emitting portion covered with a hard bake resist.
Etching is performed up to the middle of the _0.4 Ga _0.6 As clad layer (FIG. 5B). At this time, a mixed gas of chlorine and argon was used as the etching gas, and the gas pressure was 1 × 10 ⁻³ Torr,
The extraction voltage was 400V.

(213) After removing the resist,
(209) Zn by MBE method or MOCVD method
A S _0.06 Se _0.94 layer is embedded and grown (FIG. 5C).

Furthermore, 4 pairs of (211) SiO 2 are formed on the surface.
_{A 2} / α-Si dielectric multilayer film is formed by electron beam evaporation, and is removed by wet etching, leaving a region slightly smaller than the diameter of the light emitting portion (FIG. 5D). Wavelength 870nm
The reflectance of the dielectric multilayer film is 94%.

After that, a (210) p-type ohmic electrode is vapor-deposited on the surface other than the (211) dielectric multilayer film, and a (201) n-type ohmic electrode is vapor-deposited on the substrate side at 420 ° C. in an N ₂ atmosphere. By alloying, a surface emitting semiconductor laser is completed (FIG. 5E).

In the surface emitting semiconductor laser of this example thus produced, the ZnS _0.06 Se _0.94 layer used for the burying was one layer.
Since it has a resistance of GΩ or more and leakage of the injection current into the buried layer does not occur, extremely effective current confinement is achieved.
Further, since the embedded layer does not need to have a multi-layer structure, it can be easily grown and the reproducibility between batches is high. Furthermore, by using a ZnS _0.06 Se _0.94 layer whose refractive index is sufficiently smaller than that of GaAs and using an embedded refractive index waveguide structure in which an active layer is embedded,
More effective light confinement is realized.

In the embodiment of the present invention, the active layer is made of GaA.
However, similar effects can be obtained with AlGaAs.
Even when other III-V compound semiconductors are used for the columnar portion, the same effect can be obtained by selecting an appropriate II-VI compound semiconductor for the buried layer.

FIGS. 6 and 7 show another embodiment of the present invention.
FIG. 6 is a schematic view showing a cross section of a light emitting portion of a phase-locking type semiconductor laser (300) capable of enlarging a light emitting spot.
FIG. 6A is a cross-sectional view showing the manufacturing process.

On the (302) n-type GaAs substrate, (30
3) An n-type GaAs buffer layer is formed, and n-type Al _0.9 G
A 25-pair (304) semiconductor multilayer mirror having a reflectance of 98% or more with respect to light of ± 30 nm centered at a wavelength of 780 nm is formed of an a _0.1 As layer and an n-type Al _0.2 Ga _0.8 As layer. Furthermore, (305) n-type Al _0.5 Ga
_0.5 As clad layer, (306) p-type Al _{0.1 3} Ga
_0.87 As active layer, (307) p-type Al _0.5 Ga _0.5 As
A clad layer and a (308) p-type Al _0.15 Ga _0.85 As contact layer are sequentially epitaxially grown by MOCVD (FIG. 7A). The growth conditions at this time are, for example, a growth temperature of 720 ° C. and a growth pressure of 150 Torr, using TMGa (trimethylgallium) and TMAl (trimethylaluminum) organic metals as the group III source, and AsH _{3 as the} group V source. H ₂ Se was used as the n-type dopant, and DEZn (diethyl zinc) was used as the p-type dopant.

After the growth, the surface (3
12) A SiO ₂ layer is formed, a photoresist is further applied thereon, and baked at a high temperature (313) to form a hard bake resist. Further, a SiO ₂ layer is formed on this hard bake resist by the EB vapor deposition method.

Next, the reactive ion etching method (hereinafter, R
Each layer formed on the substrate is etched by using the IE method). First, (313) the SiO ₂ layer formed on the hard bake resist is subjected to a photolithography process which is usually used to form a necessary resist pattern, and this pattern is used as a mask to form a SiO film by RIE.
Etch _two layers. For example, using CF ₄ gas,
RIE is performed by controlling the gas pressure at 4.5 Pa, the input RF power at 150 W, and the sample holder at 20 ° C. Then, using this SiO ₂ layer as a mask, the (313) hard bake resist is etched by the RIE method.
For example, RIE is performed by using O ₂ gas and controlling the gas pressure at 4.5 Pa, the input power at 150 W, and the sample holder at 20 ° C. At this time, the resist pattern initially formed on the SiO ₂ layer is simultaneously etched.
Next, in order to simultaneously etch the pattern-remaining SiO ₂ layer and the (312) SiO ₂ layer formed on the epitaxial layer, etching is performed again using CF ₄ gas. By using the RIE method, which is one method of dry etching, as the hard bake resist using the thin SiO ₂ layer as a mask as described above, the side surface perpendicular to the substrate while having the required pattern shape is obtained. A hard bake resist having (313) can be created (FIG. 7B).

Using the (313) hard bake resist having the vertical side faces as a mask, a reactive ion beam etching method (hereinafter referred to as RIBE method) is used to leave a columnar light emitting portion (307) p. Type Al _0.5 Ga _0.5 As
Etching is performed up to the middle of the clad layer (Fig. 7).
(C)). At this time, a mixed gas of chlorine and argon is used as an etching gas, and the gas pressure is 5 × 10 ⁻⁴ Tor.
r, the plasma extraction voltage was 400 V, the ion current density was 400 μA / cm ² on the etched sample, and the sample holder was kept at 20 ° C. Where (307) p-type A
The reason why the l _0.5 Ga _0.5 As clad layer is etched only halfway is that the confinement of carriers and light in the horizontal direction of the active layer is made to be a refractive index waveguide type rib waveguide structure so that light in the active layer This is so that the parts can be transmitted in the horizontal direction of the active layer.

Further, by using the (313) hard bake resist having a vertical side surface and the RIBE method in which the etching is performed by vertically irradiating the etching sample with ions in the form of a beam, the (320) light-emitting portion located close to the hard baking resist is etched. Can be separated by a (314) separation groove perpendicular to the substrate, and a vertical optical resonator necessary for improving the characteristics of the surface-emitting type semiconductor laser can be manufactured.

Next, (313) after removing the hard bake resist, A is formed by the MBE method or the MOCVD method.
(309) ZnS _0.06 Se as a II-VI group compound semiconductor epitaxial layer lattice-matched to l _0.5 Ga _0.5 As
_0.94 layer is buried and grown (FIG. 7D). This (30
The layer 9) is transparent to the oscillation wavelength of the (300) surface-emitting type semiconductor laser.

Further, after removing the (312) SiO ₂ layer and the polycrystalline ZnSSe formed thereon, 4
A pair of (311) SiO ₂ / a-Si dielectric multilayer mirrors were formed by electron beam evaporation and separated by dry etching (320) and a part of the light emitting part, and (320)
The buried layer sandwiched between the light emitting parts is removed leaving (FIG. 7).
(E)). The reflectance of the dielectric multilayer film reflecting mirror at a wavelength of 780 nm is 95% or more. By forming a (311) dielectric multilayer reflector on the (314) isolation groove filled with ZnSSe, a vertical cavity structure is formed in the region sandwiched by the light emitting portions, and the (314) isolation groove is left. Light also contributes effectively to laser oscillation, and since leaked light is used,
(320) Light emission is synchronized with the phase of the light emitting unit.

Then, (311) a (310) p-type ohmic electrode is vapor-deposited on the surface other than the dielectric multilayer film reflecting mirror,
Further, a (301) n-type ohmic electrode is vapor-deposited on the substrate side, and alloying is performed at 420 ° C. in an N ₂ atmosphere.
(00) surface emitting semiconductor laser is completed (FIG. 7F).
Here, the (310) n-type ohmic electrode on the emission side is formed so as to be electrically connected to each (308) contact layer of each (320) light emitting portion.

In the surface-emitting type semiconductor laser of this example manufactured in this way, the (309) buried layer uses a ZnSSe epitaxial layer, so that the conventional AlG is used.
It has a resistance of 1 GΩ or more, which is higher than the current block structure using the reverse bias of the pn junction of the aAs layer, and has an optimum current block structure, and the buried layer absorbs the oscillation wavelength of 780 nm. Since it is a transparent material that does not have, it is possible to effectively use the leakage light from the (320) light emitting portion.

FIG. 8 shows the shapes of the conventional surface-emitting type semiconductor laser and the surface-emitting type semiconductor laser of this embodiment on the side where light is emitted and the NFP intensity distribution during laser oscillation. 8 (a) is that the writing resonator (620) to the n-p junction (607-608) <br/> Me embedded in GaAlAs epitaxial layer of a conventional surface emitting semiconductor laser shown in FIG. 12 (600) It shows a case where the distance is close to 5 μm which is a possible distance. The laser emitting surface has a dielectric multilayer mirror and a p-type ohmic electrode, but they are omitted in the figure for the purpose of comparing the shapes of the resonators. FIG. 8B shows the NFP intensity distribution between FIGS. 8A and 8B. A plurality of light emitting parts (620) of the conventional surface emitting semiconductor laser,
Even if they are brought close to the embeddable distance, only a plurality of light emission spots appear, and since there is no light leakage in the lateral direction, it becomes a multi-modal NFP and does not become one light emission spot.

FIG. 8C shows the shape of the surface-emitting type semiconductor laser of this embodiment, in which the separation groove is formed of (309) ZnS _0.06 Se.
The minimum width of the separation groove is 1 μm because it is embedded by _0.94 layer and is embedded by vapor phase growth. 8 (d) is shown in FIG. 8 (c) c.
It is NFP between -d. (314) Since light is emitted also from above the separation groove, it can be seen from the NFP that the light emitting point spreads. Since the phases of the laser beams that are closer together are synchronized,
A circular beam with an increased light output and an emission angle of 1 ° or less is obtained.

Table 2 shows the relationship between the width of the (314) separation groove of the (300) surface-emitting type semiconductor laser of the embodiment and the oscillation transverse mode order measured from NFP.

[0056]

[Table 2] When the width is narrower than 10 μm, the phase-locked laser oscillation transverse mode oscillates in the fundamental mode, but above that, laser oscillation occurs in the higher-order modes higher than the first order, and the radiation angle widens or the beam shape becomes elliptical. Therefore, it is not preferable in application. In addition, a circular beam tends to be difficult to obtain with a separation groove narrower than 0.5 μm.

In the above-mentioned embodiment, the semiconductor laser having one optical resonator in which a plurality of light emitting portions are separately provided has been described, but a plurality of such optical resonators may be formed on the same semiconductor substrate. it can. When the p-type ohmic electrode on the light emitting side is independently provided for each optical resonator, the laser beam from each optical resonator can be independently turned on, off, and modulated.

Although the GaAlAs-based surface-emitting type semiconductor laser has been described in the above embodiment, it can be suitably applied to other III-V group surface-emitting type semiconductor lasers as described above, and particularly the active layer. In addition to Ga _0.87 Al _0.13 As, the oscillation wavelength can be changed by changing the composition of Al.

Although the present embodiment has been described based on the structure shown in FIG. 6 and the structure of the light emitting portion shown in FIG. 8C, the present invention is not limited to this. 9 to 11
FIG. 4 shows another embodiment of the present invention, and is a schematic view of a light emitting portion showing the shape of a plane horizontal to the substrate of an optical resonator and a separation groove formed inside the resonator when viewed from the light emitting side. is there. In FIGS. 9A to 9J and 9M, a plurality of substrates each having a columnar semiconductor layer having a horizontal cross section of a circle or a regular polygon are formed and arranged in line symmetry. In each case, the light emission spot can be enlarged more than that having one light emitting unit. When a laser beam having a relatively large beam diameter having one light beam is obtained from each light emitting portion and the separation groove, FIG.
As shown in (k) and (l), a circular beam can be obtained even if the cross-sectional shape of each light emitting portion is a shape other than a circle or a regular polygon. The outline shape in which the outer edges of the non-circular and non-regular polygonal light emitting portions arranged in line symmetry are connected may be a circle or a shape close to a regular polygon. In addition, FIG.
(D) and the examples shown in FIGS. 11 (a) to (c) respectively form n light emitting portions, and in this example, the same effect as that of the example shown in FIG. 6 can be obtained. In addition, the effect that the light emission spot can be formed in an arbitrary size and shape is obtained. 10 and 11, a line beam can be obtained by arranging a plurality of light emitting units at equal intervals in rows and / or columns on a two-dimensional surface parallel to the substrate.

In the embodiment shown in FIG. 6, (31
It is also possible to manufacture a semiconductor laser in which 0) p-type ohmic electrodes are provided separately for each (320) light emitting portion and each is connected to the (308) contact layer. In this case, a plurality of light emitting portions each capable of independently controlling ON / OFF and modulation of a circular beam are formed on the same substrate, and the wavelengths of the respective beams are synchronized.

The surface-emitting type semiconductor laser of the present invention can be applied not only to printing devices such as printers and copying machines, but also to
It goes without saying that the same effect can be obtained for a facsimile and a display.

[0062]

[0063]

[Brief description of drawings]

FIG. 1 is a perspective view showing a cross section of a light emitting portion of a semiconductor laser according to an embodiment of the present invention.

2A to 2E are cross-sectional views showing a manufacturing process of the semiconductor laser of FIG.

FIG. 3 is a diagram showing the relationship between the drive current and the oscillation light output of the semiconductor laser of FIG.

FIG. 4 is a perspective view showing a cross section of a light emitting portion of a semiconductor laser according to another embodiment of the present invention.

5A to 5E are cross-sectional views showing a manufacturing process of the semiconductor laser of FIG.

FIG. 6 is a schematic view showing a cross section of a light emitting portion of a phase-locking surface-emitting type semiconductor laser in an example of the present invention.

7A to 7F are cross-sectional views showing a manufacturing process of the semiconductor laser of FIG.

FIG. 8 is a diagram showing a difference in shape and a difference in emission near-field image between the conventional surface-emitting type semiconductor laser and the semiconductor laser shown in FIG. 6, in which FIG. The shape on the side of emission is shown, and the figure (b) shows the intensity distribution of the emission far-field image of the semiconductor laser shown in the figure (a). FIG. 7C shows an example of the shape of the side of the semiconductor laser from which light is emitted in this embodiment, and FIG. 7D shows the emission far field of the semiconductor laser shown in FIG. 3 is a diagram showing the intensity distribution of an image.

9 (a) to 9 (m) are schematic views showing the shape on the light emitting side of a phase-locking surface-emitting type semiconductor semiconductor laser according to another embodiment of the present invention.

10 (a) to 10 (d) are schematic views showing the shape on the light emitting side of a phase-locking surface-emitting type semiconductor laser according to another embodiment of the present invention.

11 (a) to (c) are schematic views showing the shape of a phase-locking surface-emitting type semiconductor laser on the side from which light is emitted in another embodiment of the present invention.

FIG. 12 is a perspective view showing a light emitting portion of a conventional surface emitting semiconductor laser.

[Explanation of symbols]

102, 202, 302 Semiconductor substrates 106, 206, 306 Active layers 107, 207, 307 Clad layers 108, 208, 308 Contact layers 109, 209, 309 II-VI group compound semiconductor epitaxial layers 111, 211, 311 Light emission side reflection Mirror 314 Separation groove 320 Light emitting part

─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A 63-188983 (JP, A) JP-A 2-54981 (JP, A) JP-A 1-289291 (JP, A) JP-A 64-- 44083 (JP, A) JP 64-66988 (JP, A) JP 64-50431 (JP, A) JP 63-7692 (JP, A) JP 2-198184 (JP, A) JP-A-2-128481 (JP, A) JP-A-5-508971 (JP, A) Electron. Lett. Vol. 26 No. 1 (1990) p. 18-19 (58) Fields investigated (Int.Cl. ⁷ , DB name) H01S 5/00-5/50

Claims (8)

(57) [Claims] 1. A semiconductor substrate, a lower reflecting mirror formed above the semiconductor substrate, and a lower cladding layer formed above the lower reflecting mirror,
An optical resonator including an active layer formed above the lower clad layer, and an upper clad layer formed above the active layer and having a columnar part in the upper part, and an upper part formed above the columnar part. A plurality of light emitting portions are formed in the optical resonator by a separation groove that divides the columnar portion and does not reach the active layer, and the upper reflecting mirror includes at least the A surface-emitting type semiconductor laser characterized by being formed on a separation groove. 2. The surface emitting semiconductor laser according to claim 1, wherein the width of the separation groove is 5 μm or less. 3. The plurality of light emitting portions have a cross-sectional shape parallel to the semiconductor substrate that is either a circle or a regular polygon, and either the diameter of the circle or the diagonal line of the regular polygon, 3. The surface emitting semiconductor laser according to claim 1, wherein the surface emitting semiconductor laser has a thickness of less than 10 μm. 4. The contact layer has a thickness of 3.0 μm.
The surface emitting semiconductor laser according to claim 1, wherein: 5. The surface emitting semiconductor laser according to claim 1, further comprising a region serving as a light emitting portion corresponding to each of the columnar portions. 6. The surface emitting semiconductor laser according to claim 1, wherein an epitaxial layer of a II-VI group compound semiconductor is formed around the columnar portion. 7. The II-VI group compound semiconductor is selected from at least one element selected from Group II elements Zn, Cd, and Hg and from Group VI elements O, S, Se, and Te. 7. A surface-emitting type semiconductor laser according to claim 6, which is a II-VI group compound semiconductor composed of at least one selected element. 8. The II-VI group compound semiconductor is ZnSe or Zn.
8. The surface emitting semiconductor laser according to claim 7, wherein the surface emitting semiconductor laser is any one of S, ZnSSe, ZnCdS, and CdSSe.