JPH08236858A - P-type substrate buried type semiconductor laser and its manufacture - Google Patents

Abstract

PURPOSE: To provide a buried type semiconductor laser which uses a P-type substrate and is excellent in high temperature characteristics, and its manufacturing method. CONSTITUTION: In a P-type substrate buried type semiconductor laser formed on a P-type semiconductor substrate 1, the peripheral part of at least an active layer stripe region is dug to a depth reaching a P-type first semiconductor layer 2, and this part is filled in order, from the substrate side, with a P-type first semiconductor layer 3, an N-type first semiconductor layer 4, a P-type first semiconductor layer 5, and a second semiconductor layer 6 whose band gap is smaller than that of the first semiconductor. Further, the whole part is filled with N-type first semiconductor 7. The distance between the second semiconductor layer 6 and an active layer 9 is larger than about 0.6μm. The carrier concentration of the P-type first semiconductor layer 3 adjacent to the active layer 9 is at most 1×10<18> cm<-3> . The band gap wavelength of the second semiconductor layer is shorter than the oscillation wavelength of laser.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a semiconductor laser, and more particularly to an array semiconductor laser used for optical interconnection of a computer, an exchange, etc., a semiconductor laser for optical communication, and a manufacturing method thereof.

[0002]

2. Description of the Related Art A conventional semiconductor laser of this type is, for example, a DC-PBH (double-channel-planar-buried-het).
The erostructure laser has a buried structure whose cross-sectional structure is shown in FIG. 10, and was a device excellent in high-temperature and high-power operation (see, for example, Mito et al., “In.
GaAsP Double-Channel-Palnar-Buried-Hete
rostructure Laser Diode (DC-PBH LD) Wit
h Effective Current Configuration ”, JLT, vol.LT-
1, No.1, pp.185-202, 1983).

In FIG. 10, 34 is an n-type InP (001) substrate, 35 is an n-type InP buffer layer, 36 is an n-type InP clad layer, 37 is an InGaAsP layer, 38 is a p-type InP clad layer, and 39 is an InGaAsP active layer. A layer, 40 is a p-type InP current blocking layer, 41 is an n-type InP current blocking layer, and 42 is a p-type InP buried layer.

The conventional DC-PBH laser shown in FIG.
Since the mold substrate is used, when the elements are formed in an array, the n-side becomes the common electrode.

However, in recent years, ECL driving by an npn bipolar transistor has been favorably used, so that an embedded laser on a p-type substrate has been demanded.

In a structure in which the n-type semiconductor and the p-type semiconductor are simply replaced in the DC-PBH laser, the side (side surface) of the active layer becomes the n-type semiconductor layer. That is, InGa in FIG.
The side of the AsP active layer 39 becomes the p-type InP current blocking layer 40 to the n-type current blocking layer.

[0007]

In this case, since the electron has a higher mobility than the hole, the leak current flowing beside the active layer is large, and the characteristics are the same as those of the conventional DC-PBH laser on the n-type substrate. There was a problem that I could not hope.

In recent years, a PBH (planar-burie) in which a side of an InGaAsP active layer 50 as shown in FIG. 11, which is produced by performing crystal growth on a p-type substrate, is filled with a p-type semiconductor layer, is used.
d-heterostructure) lasers have been reported (eg, Okura et al., "Low Threshold FS-BH Laser").
n p-InP Substrate Grown by All-MOCVD ”,
Electron. Lett., Vol.28, No.19, pp.1844-1845, 19
See 1992).

In FIG. 11, 43 is a p-type InP (001) substrate, 44 is a p-type InP buffer layer, 45 is a p-type InP buried layer, 46 is an n-type InP current blocking layer, and 47 is p-type In.
P current blocking layer, 48 n-type InP buried layer, 49 p
Type InP clad layer, 50 is an InGaAsP active layer, and 51 is an n type InP clad layer.

However, in the PBH laser of FIG. 11, the current block structure is not appropriate, and thus the high temperature and high output characteristics as good as those of the conventional n-type substrate DC-PBH laser are not obtained.

On the other hand, RIBPBH (recombinat
ion layer-inserted-blocking-planar-buried-heterost
The laser has a recombination layer (i-InGaAsP recombination layer) 57 inserted in the current block layer as shown in FIG. 12, and the leakage current flowing through the current block layer is suppressed, so that the DC-PBH Excellent characteristics can be expected even at high temperature and high output like a laser (for example, JP-A-6-3386).
No. 54 (Japanese Patent Application No. 5-127221).

In FIG. 12, 52 is a p-type InP (001) substrate, 53 is a p-type InP buffer layer, 54 is a p-type InP buried layer, 55 is an n-type InP current blocking layer, and 56 is p-type In.
P current blocking layer, 57 is i-InGaAsP recombination layer,
Reference numeral 58 is an n-type InP buried layer, 59 is a p-type InP clad layer, 60 is an InGaAsP active layer, and 61 is an n-type InP clad layer.

However, the structure is not sufficiently limited, and for example, i
-InGaAsP recombination layer 57 and InGaAsP active layer 60
If the distance is not sufficiently large, the potential for holes in the recombination layer is low, and conversely, the light passes directly through the p-type semiconductor layers (p-type InP buried layer 54) on both sides of the active layer and directly enters the i-In.
There is a problem that the leakage current flowing into the GaAsP recombination layer 57 increases.

Therefore, an object of the present invention is to eliminate the problems of the conventional embedded laser formed on the p-type substrate and to provide an embedded structure capable of realizing good characteristics.

[0015]

In order to achieve the above object, the present invention provides a buried type semiconductor laser formed on a substrate made of a first semiconductor having a conductivity type of p type, in which at least an active layer stripe region is formed. The peripheral part is p-type 1st
Of the p-type first semiconductor layer, the n-type first semiconductor layer, and the p-type first semiconductor layer are sequentially formed from the substrate side. Semiconductor layer,
And a second band gap smaller than that of the first semiconductor
Embedded in the semiconductor layer, and has a structure in which the entire semiconductor layer is embedded with an n-type first semiconductor.
A semiconductor laser of the p-type substrate embedded type is provided, wherein the semiconductor layer is provided at a predetermined distance from the active layer.

The p-type substrate-embedded semiconductor laser of the present invention is preferably characterized in that the distance between the second semiconductor layer and the active layer is approximately 0.6 μm or more.

In the p-type substrate-embedded semiconductor laser of the present invention, preferably, the carrier concentration of the p-type first semiconductor layer adjacent to the active layer is 1 × 10 ¹⁸ cm ⁻³ or less. And

The p-type substrate-embedded semiconductor laser of the present invention is preferably characterized in that the bandgap wavelength of the second semiconductor layer is shorter than the oscillation wavelength of the laser.

Further, according to the present invention, in a buried semiconductor laser formed on a substrate made of a first semiconductor having a p-type conductivity, at least a peripheral portion of an active layer stripe region has a p-type first semiconductor layer. To a depth reaching up to, and the engraved peripheral portion is sequentially p from the substrate side.
Type first semiconductor layer, an n-type first semiconductor layer, a p-type first semiconductor layer, and a second semiconductor layer having a bandgap smaller than that of the first semiconductor, and further the whole. Has a structure embedded with an n-type first semiconductor, and the carrier concentration of the p-type first semiconductor layer adjacent to the active layer is approximately 1 × 10 ¹⁸ cm ⁻³ or less. Provided is a p-type substrate-embedded semiconductor laser.

Further, according to the present invention, in a buried semiconductor laser formed on a substrate made of a first semiconductor having a conductivity type of p type, at least a peripheral portion of an active layer stripe region has a first semiconductor layer of p type. To a depth reaching up to, and the engraved peripheral portion is sequentially a p-type first semiconductor layer, an n-type first semiconductor layer, and a p-type first semiconductor layer from the substrate side. , And a second semiconductor layer having a band gap smaller than that of the first semiconductor,
Further, a p-type substrate-embedded semiconductor having a structure in which the whole is buried with an n-type first semiconductor, and the bandgap wavelength of the second semiconductor layer is shorter than the oscillation wavelength of the laser. Provide a laser.

The present invention also relates to organic vapor deposition (MOVP).
A method for manufacturing a p-type substrate-embedded semiconductor laser using a thin film forming method such as E) method, comprising: (a) excluding an active layer stripe region on a substrate made of a first semiconductor whose conductivity type is p-type. Forming a p-type first semiconductor layer, an active layer and an n-type first semiconductor layer on a peripheral portion of the active layer, and (b) removing the mask and removing the active layer. Forming a mask made of a dielectric on the n-type first semiconductor layer formed on the upper layer, and (c) sequentially forming a p-type first semiconductor layer on the peripheral portion of the active layer stripe region. , An n-type first semiconductor layer and a p-type first semiconductor layer are sequentially buried and grown, and a second semiconductor layer is formed at a distance of approximately 0.6 μm or more from the active layer in the stacking direction. (D) After removing the mask, the entire area including the active layer stripes is n. Providing burying the first semiconductor layer, a p-type substrate buried-type semiconductor laser manufacturing method, which comprises a.

Furthermore, the present invention is directed to organic vapor deposition (MOV).
A method for manufacturing a p-type substrate-embedded semiconductor laser using a thin film forming method such as PE), wherein (a) a p-type first semiconductor is formed on a substrate made of a first semiconductor having a p-type conductivity. A step of producing a laser source crystal by sequentially laminating the semiconductor layer, the active layer and the n-type first semiconductor layer, and (b) a mask made of a dielectric material is provided on the laser source crystal to obtain a width of the semiconductor layer. Forming a mesa stripe by etching to a depth smaller than the width of the mask by about 0.6 μm or more on both sides and reaching the p-type first semiconductor layer, (c)
A p-type first semiconductor layer, an n-type first semiconductor layer, and a p-type first semiconductor layer are sequentially buried and grown in the peripheral portion of the mesa stripe region, and the p-type first semiconductor is further grown. Forming a second semiconductor layer on the layer above the mask, and (d) removing the mask and then filling the whole including the mesa stripe with an n-type first semiconductor layer. A method of manufacturing a p-type substrate-embedded semiconductor laser is provided.

The present invention, in a preferred embodiment,
A p-type substrate-embedded semiconductor laser having a double hetero structure, wherein a mesa stripe region including a p-type clad layer, an active layer, and an n-type clad layer is formed on a p-type semiconductor substrate via a buffer layer made of a p-type semiconductor. A region extending from the side surface of the mesa stripe region to the buffer layer is buried with a buried layer made of a p-type semiconductor, and an n-type current block layer and a p-type current block layer are sequentially formed on the buried layer, A p-type substrate-embedded semiconductor laser in which a recombination layer having a bandgap wavelength shorter than the oscillation wavelength of the laser is provided on the current blocking layer with a predetermined distance from the active layer, and the whole is covered with an n-type embedding layer I will provide a. In the present invention, the active layer may have a multi-quantized well (MQW) structure.

[0024]

The operation and principle of the present invention will be described below.

In a semiconductor laser formed on a p-type substrate, in order to realize a low threshold current and a high slope efficiency, it is important to reduce unnecessary leakage current flowing in a portion other than the active layer. The leakage current flowing on both sides of the active layer is
It is suppressed to some extent by the npnp structure of the current blocking layer.

However, when both sides of the active layer are filled with the n-type current blocking layer, the mobility of electrons is considerably higher than the mobility of holes, so that the electrons move from the n-type cladding layer above the active layer. It easily flows into the n-type current blocking layer and is easily injected into the pn junction of the channel portion, so that the characteristics of the laser are significantly deteriorated.

In the conventional DC-PBH laser, the semiconductor conductivity type is inverted (p-type and n-type are inverted).
Both sides of the active layer were filled with the n-type semiconductor layer, and the flow of electrons from the upper part of the active layer to the n-type current blocking layer was unavoidable. Therefore, it is considered that this flow of electrons can be suppressed to some extent by burying the p-type semiconductor on both sides of the active layer.

On the other hand, the recently reported PBH laser which is produced by crystal growth on a p-type substrate is embedded so that the p-type semiconductor is located on both sides of the active layer, and the conventional DC is used. In the -PBH laser, the flow of electrons flowing from the upper part of the active layer to the n-type current blocking layer can be suppressed as in the structure in which the conductivity type of the semiconductor is inverted.

In the case of this PBH laser, the leakage current flowing on both sides of the active layer is blocked by the pnpn thyristor structure of the current block layer, but it flows from the p-type substrate into the p-type current block layer and the n-type current block in the upper part. The presence of holes flowing into the layer was unavoidable.

FIG. 6 shows a thyristor structure. The thyristor has a pnpn structure. The p1 region is called an anode and the n2 region is called a cathode. When a positive voltage (+ V) is applied to the anode, the pn junction J2 is reverse biased up to a predetermined voltage V _FB, so that almost no current flows. Does not flow (referred to as “off state”), but when the applied voltage becomes V _FB , electrons and holes generated by the avalanche at the pn junction J2 are n respectively.
1. Enter the p2 region and bias the pn junctions J1 and J3 in the forward direction, and holes and electrons in the p1 region and the n2 region are injected into the depletion layer of the pn junction J2 through the n1 region and the p2 region. The junctions J1 and J3 are further biased in the forward direction to further increase the injection of holes and electrons, and the voltage between the anode and the cathode is lowered to the holding voltage V _H (referred to as “on state”). The turn-on of the thyristor when the forward bias is applied is promoted by the decrease of the diffusion potential at the pn junction J3 caused by the holes flowing from the p2 region to the n2 region shown in FIG.

Since the RIBRBH laser has the p1 layer, the n1 layer, the p2 layer, and the layer having a bandgap smaller than that of the n2 layer at a position corresponding to the pn junction J3 in FIG. 6, electrons and electrons flowing from the n-type current blocking layer to the p-type layer are generated. The holes that flow from the p-type current blocking layer to the n-type layer are absorbed, and the decrease in diffusion potential at each position is prevented.

As a result, it is difficult to turn on the current blocking layer. On the contrary, since the recombination layer has a low potential for holes, there is a problem that a leak current that passes through the p-type semiconductor layers on both sides of the active layer and directly flows into the recombination layer increases.

FIG. 7 shows the current-light output characteristics at 85 ° C. when the distance between the recombination layer and the active layer is changed and calculated using a two-dimensional optical device simulator.

From FIG. 7, the distance between the active layer and the recombination layer is 0.
When it is as small as 4 μm, the threshold current is increased and the slope efficiency is decreased as compared with the case of 0.6 and 1.0 μm. Therefore, it is understood that the distance between the active layer and the recombination layer needs to be 0.6 μm or more.

FIG. 8 shows the carrier concentration dependence of the threshold value at 85 ° C. and slope efficiency at 85 ° C.-5 mW calculated by using a two-dimensional device simulator in the p-type buried layer.

From FIG. 8, the slope efficiency hardly changes, but when it is 1 × 10 ¹⁸ cm ⁻³ or more, the threshold value becomes ³ mA or more as compared with the case of 1 × 10 ¹⁷ cm ⁻³ , which is the smallest threshold value. You can see that

FIG. 9 shows the dependence of the recombination layer composition on the threshold and slope efficiency of the RIBPBH laser having an oscillation wavelength of 1.3 μm at 85 ° C. calculated using a two-dimensional device simulator.

From FIG. 9, the composition wavelength of the recombination layer is about 1.2 μm.
It can be seen that when m is set, the threshold value is the lowest, the slope efficiency is good, and the leakage current of electrons and holes can be minimized.

In the present invention, the distance between the recombination layer and the active layer is
0.6 μm or more, the carrier concentration of the p-type semiconductor layers on both sides of the active layer is 1 × 10 ¹⁸ cm ⁻³ or less, and the composition wavelength of the recombination layer is shorter than the oscillation wavelength of the laser. As a result, by reducing the electric resistance to holes, the leakage current flowing through the p-type semiconductor layers on both sides of the active layer and directly flowing into the recombination layer is suppressed, and the p-type substrate on the high-temperature operation is excellent. An embedded semiconductor laser is obtained.

[0040]

Embodiments of the present invention will be described with reference to the drawings.

[0041]

Embodiment 1 FIGS. 2 and 3 are views showing a manufacturing process of an InGaAsP / InP based buried type semiconductor laser which is a first embodiment of the present invention.

First, as shown in FIG. 2A, p-In
MOVPE (Metal Organic Vapor) on P (001) substrate 11
Phase Epitaxial grouth; metal-organic vapor phase epitaxial growth) method was used to p-InP buffer layer 12 (Z
n: 7 × 10 ¹⁷ cm ⁻³ doped) 0.2 μm and then S
The io ₂ film 13 is formed, and the SiO ₂ film 13 is used as a mask for MOV.
P-InP clad layer 14 (Zn: 7 × 10 ¹⁷ cm by PE method)
^-3 doped), InGaA with bandgap wavelength 1.31 μm
sP active layer 15, n-InP clad layer 16 (Si: 1.2 × 1
0 ¹⁸ cm ^-3 doped) 0.3 μm was grown in sequence and DH (Double
Heterostructure (double hetero junction) wafer is produced.

Although the MOVPE method is used in this embodiment, this can also be applied to the MBE (Molecular Beam Epitaxy) method and the like.

The active layer is made of InGaAs having a composition of 1.13 μm.
P SCH (Separated Confinement Heterostractur
e; separate confinement structure) layer 60 nm, 5.7 nm thick 1.40
μm composition InGaAsP well (non-doped), and
10-nm thick 1.13 μm InGaAsP barrier (undoped) 7-layer multiple quantum well
ll; MQW) structure and 1.13 μm composition InGaAsP
MQW like 60W SCH layer MQW active layer
With the structure, better characteristics can be expected. In addition, SCH
The structure is a structure in which a quantum well is sandwiched between optical waveguide layers with a low refractive index and a large bandgap energy, light is confined in the optical waveguide layer and electrons are separately confined in the quantum well layer, and light is sufficiently confined. is there.

Next, as shown in FIG. 2B, the SiO ₂ film 1
After removing 3, the SiO ₂ film 17 is formed on the mesa stripe region.
To form.

Further, as shown in FIG. 3C, p is formed on both sides of the active layer except the mesa stripe region by MOVPE method.
-InP buried layer 18 (Zn: 5 x 10 ¹⁷ cm ^-3 ), n-
InP current blocking layer 19 (Si: 1 × 10 ¹⁸ cm ⁻³ ), p
-InP current blocking layer 20 (Zn: 1 x 10 ¹⁸ cm ^-3 ),
i-InGaAsP recombination layer 21 (1.20 μm composition, 0.1 μm
m thickness) is sequentially buried and grown.

Here, the i-InGaAsP recombination layer 21 is formed at a distance of about 1.0 μm from the active layer in the stacking direction (see FIG. 1). Although the MOVPE method was used in this embodiment,
This is also possible in the LPE (Liquid Phase Epitaxy) method or the MBE method.

Further, as shown in FIG. 3D, n-InP
By growing the buried layer 22 (Si: 1.2 × 10 ¹⁸ cm ⁻³ ), the buried semiconductor laser on the p-type substrate shown in FIG. 1 is obtained.

Referring to FIG. 1, the peripheral portion of the active layer stripe region is dug to a depth reaching p-type InP buffer layer 2, and this dug portion is p-type InP.
(001) p-type InP buried layer 3, n-type InP current blocking layer 4, p-type InP current blocking layer 5 in order from the substrate 1 side
And i-InGaA with bandgap wavelength of 1.20 μm
Buried by sP recombination layer 6 and entirely n-type In
I-I
The nGaAsP recombination layer 6 is substantially the same as the InGaAsP active layer 9.
They are separated by about 1.0 μm.

[0050]

Second Embodiment Next, a second embodiment of the present invention will be described. FIGS. 4 and 5 show InG which is a second embodiment of the present invention.
It is a figure which shows the manufacturing process of an aAsP / InP system embedded semiconductor laser.

First, as shown in FIG. 4A, p-type In
The p-type In is formed on the P (001) substrate 23 by the MOVPE method.
P buffer layer 24 (Zn: 7 × 10 ¹⁷ cm ⁻³ doped) 0.5
After the growth of μm, a p-type InP clad layer 25 (Zn: 7 × 10 ¹⁷ cm ⁻³ doping), an InGaAsP active layer 26 with a bandgap wavelength of 1.31 μm, and an n-type InP clad layer 27 (Si: 1.2 ×) were formed by MOVPE. 10 ¹⁸ cm ⁻³ doped) 0.6 μm is sequentially grown to prepare a DH wafer. In this embodiment, M
Although the OVPE method is used, the MBE method or the like may be used.

Further, the active layer is made of InGaAs with a composition of 1.13 μm.
1.40 μm composition InG with 60 nm and 5.7 nm thickness of P SCH layer
aAsP well (undoped) and 10 nm thick 1.13μ
7 composed of m composition InGaAsP barrier (non-doped)
Layered multiple quantum well (MQW) structure and 1.13 μm composition I
If an MQW structure such as MQW composed of an nGaAsP SCH layer of 60 nm is used, even better characteristics can be expected.

Next, as shown in FIG. 4B, a mesa stripe is formed on the MQW wafer by a Br-methanol-based etchant using the SiO ₂ stripe mask 28 for forming a mesa.

At this time, the width of the semiconductor layer is smaller than the width of the SiO ₂ stripe mask 28 by 1.0 μm on both sides, and p
Etch to a depth that reaches the first semiconductor layer of the mold.
Although the wet etching method was used in this embodiment,
This is also possible in the dry etching method.

Next, as shown in FIG. 5 (c), the formed mesa stripe was formed by using the MOVPE method on the p-type InP buried layer 29 (Zn: 5 × 10 ¹⁷ cm ⁻³ ), the n-type InP current blocking layer. 30 (Si: 1 × 10 ¹⁸ cm ⁻³ ), p-type InP current blocking layer 31 (Zn: 1 × 10 ¹⁸ cm ⁻³ ), i-InGa
An AsP recombination layer 32 (1.20 μm composition, 0.1 μm thickness) is sequentially embedded and grown.

If the i-InGaAsP recombination layer 32 is formed above the SiO ₂ stripe mask 28,
The active layer and the i-InGaAsP recombination layer 32 are 1.
It is formed with a distance of 0 μm or more. In this embodiment, MO
Although the VPE method is used, the LPE method or the MBE method may be used.

Further, as shown in FIG. 5D, n-type InP
By growing the buried layer 33 (Si: 1.2 × 10 ¹⁸ cm ⁻³ ), the buried semiconductor laser on the p-type substrate shown in FIG. 1 is obtained.

Although the present invention has been described with reference to each of the above embodiments, the present invention is not limited to the above embodiments, and it is needless to say that various embodiments according to the principle of the present invention are included. For example, the present invention is based on the InGaA shown in the above embodiment.
AlGa as well as sP / InP embedded lasers
It can also be applied to an As / GaAs embedded laser and the like.

[0059]

As described above, according to the semiconductor laser of the present invention, it is possible to solve the problems of the RIBPBH laser having the conventional structure and to provide a semiconductor laser excellent in high temperature characteristics while using a p-type substrate. Can be done. Further, in the present invention, when the composition wavelength of the recombination layer is shorter than the oscillation wavelength of the laser, the threshold value is low, the slope efficiency is good, and the leakage current of electrons and holes can be minimized. .

Further, according to the manufacturing method of the present invention, the leakage current passing through the p-type semiconductor layers on both sides of the active layer and directly flowing into the recombination layer is suppressed, a p-type substrate is used, and the high temperature characteristics are excellent. It is possible to manufacture a semiconductor laser.

[Brief description of drawings]

FIG. 1 is an InGaAsP / InP according to an embodiment of the present invention.
It is a figure explaining a system MQW embedded type semiconductor laser.

FIG. 2 is a diagram showing a method of manufacturing the semiconductor laser according to the first embodiment of the present invention in the order of steps.

FIG. 3 is a diagram showing a method of manufacturing the semiconductor laser according to the first embodiment of the present invention in the order of steps.

FIG. 4 is a diagram showing a method of manufacturing a semiconductor laser according to a second embodiment of the present invention in the order of steps.

FIG. 5 is a diagram showing a method of manufacturing a semiconductor laser according to a second embodiment of the present invention in the order of steps.

FIG. 6 is a structural schematic diagram for explaining the present invention and is a diagram showing a thyristor structure.

FIG. 7 is a diagram showing the distance dependence of the current-light output characteristics between the active layer and the recombination layer for explaining the present invention.

FIG. 8 is a graph showing the dependence of threshold value and slope efficiency on the carrier concentration of p-type buried layer for explaining the present invention.

FIG. 9 is a diagram showing the wavelength dependence of the recombination layer composition of the threshold value and slope efficiency for explaining the present invention.

FIG. 10 is a cross-sectional view for explaining a conventional DC-PBH structure semiconductor laser.

FIG. 11 is a sectional view for explaining a conventional PBH structure semiconductor laser on a p-type substrate.

FIG. 12 is a sectional view for explaining a conventional RIBPBH structure semiconductor laser.

[Explanation of symbols]

1 p-InP (001) substrate 2 p-InP buffer layer 3 p-InP buried layer 4 n-InP current blocking layer 5 p-InP current blocking layer 6 i-InGaAsP recombination layer 7 n-InP buried layer 8 p- InP clad layer 9 InGaAsP active layer 10 n-InP clad layer 11 p-InP (001) substrate 12 p-InP buffer layer 13 SiO ₂ film 14 p-InP clad layer 15 InGaAsP active layer 16 n-InP clad layer 17 SiO ₂ Film 18 p-InP buried layer 19 n-InP current blocking layer 20 p-InP current blocking layer 21 i-InGaAsP recombination layer 22 n-InP buried layer 23 p-InP (001) substrate 24 p-InP buffer layer 25 p -InP cladding layer 26 InGaAsP active layer 27 n-InP cladding layer 28 SiO ₂ film (SiO ₂ stripe squares ) 29 p-InP buried layer 30 n-InP current blocking layer 31 p-InP current blocking layer 32 i-InGaAsP recombination layer 33 n-InP buried layer 34 n-InP (001) substrate 35 n-InP buffer layer 36 n -InP clad layer 37 InGaAsP layer 38 p-InP clad layer 39 InGaAsP active layer 40 p-InP current blocking layer 41 n-InP current blocking layer 42 p-InP buried layer 43 p-InP (001) substrate 44 p-InP buffer Layer 45 p-InP buried layer 46 n-InP current blocking layer 47 p-InP current blocking layer 48 n-InP buried layer 49 p-InP clad layer 50 InGaAsP active layer 51 n-InP clad layer 52 p-InP (001) Substrate 53 p-InP buffer layer 54 p-InP buried layer 55 n-InP current blocking layer 56 p-InP current layer Blocking layer 57 i-InGaAsP recombination layer 58 n-InP buried layer 59 p-InP cladding layer 60 InGaAsP active layer 61 n-InP cladding layer

Claims (11)

[Claims] 1. In a buried semiconductor laser formed on a substrate made of a first semiconductor having a p-type conductivity, at least a peripheral portion of an active layer stripe region reaches a depth reaching the p-type first semiconductor layer. And the dug-down peripheral portion is sequentially p-type first semiconductor layer, n-type first semiconductor layer, p-type first semiconductor layer, and first Second semiconductor layer having a bandgap smaller than that of the first semiconductor, and the entire second semiconductor layer is buried with an n-type first semiconductor. A p-type substrate-embedded semiconductor laser provided with a distance. 2. The distance between the second semiconductor layer and the active layer is approximately 0.6 μm or more.
The p-type substrate-embedded semiconductor laser described above. 3. A buried semiconductor laser formed on a substrate made of a first semiconductor having a p-type conductivity, wherein at least the peripheral portion of the active layer stripe region reaches a depth reaching the p-type first semiconductor layer. And the dug-down peripheral portion is sequentially p-type first semiconductor layer, n-type first semiconductor layer, p-type first semiconductor layer, and first Of the p-type first semiconductor adjacent to the active layer, the second semiconductor layer having a bandgap smaller than that of the first semiconductor and further having a structure of being entirely embedded with the n-type first semiconductor. P-type substrate-embedded semiconductor laser having a carrier concentration of about 1 × 10 ¹⁸ cm ⁻³ or less. 4. A buried semiconductor laser formed on a substrate made of a p-type first semiconductor of a conductivity type, wherein at least a peripheral portion of an active layer stripe region reaches the p-type first semiconductor layer. The first part of the p-type is dug in the depth, and the dug-down peripheral portion is sequentially formed from the substrate side.
Of the semiconductor layer, the n-type first semiconductor layer, the p-type first semiconductor layer, and the second semiconductor layer having a bandgap smaller than that of the first semiconductor. A p-type substrate-embedded semiconductor laser having a structure embedded with a first semiconductor, wherein the bandgap wavelength of the second semiconductor layer is shorter than the oscillation wavelength of the laser. 5. The p-type substrate-embedded type according to claim 1, wherein the p-type first semiconductor layer adjacent to the active layer has a carrier concentration of 1 × 10 ¹⁸ cm ⁻³ or less. Semiconductor laser. 6. The p-type substrate-embedded semiconductor laser according to claim 1, wherein the bandgap wavelength of the second semiconductor layer is shorter than the oscillation wavelength of the laser. 7. The p-type substrate-embedded semiconductor laser according to claim 3, wherein the bandgap wavelength of the second semiconductor layer is shorter than the oscillation wavelength of the laser. 8. A method for manufacturing a p-type substrate-embedded semiconductor laser using a thin film forming method such as organic vapor phase epitaxy (MOVPE) method, comprising: (a) starting from a first semiconductor having a p-type conductivity. A mask made of a dielectric material is formed on the peripheral portion of the substrate except the active layer stripe region, and the p-type first semiconductor layer, the active layer, and the n-type are formed.
Forming a first semiconductor layer of a positive type, and (b) forming a mask made of a dielectric on the first semiconductor layer of the n type formed on the active layer after removing the mask. And (c) a p-type first semiconductor layer, an n-type first semiconductor layer, and a p-type first semiconductor layer are sequentially buried and grown in the peripheral portion of the active layer stripe region, and further, Forming a second semiconductor layer at a distance of approximately 0.6 μm or more from the active layer in the stacking direction, and (d) removing the mask, and then forming an entire n-type first semiconductor including the active layer stripe. A method of manufacturing a p-type substrate-embedded semiconductor laser, comprising: a step of embedding a layer. 9. A method for manufacturing a p-type substrate-embedded semiconductor laser using a thin film forming method such as organic vapor phase epitaxy (MOVPE) method, which comprises (a) a first semiconductor having a p-type conductivity. On the substrate
Forming a laser source crystal by sequentially stacking a first semiconductor layer of a p-type, an active layer, and a first semiconductor layer of an n-type; and (b) providing a mask made of a dielectric material on the laser source crystal,
The width of the semiconductor layer is approximately 0.6 μm on both sides of the width of the mask.
A step of forming a mesa stripe by etching to a depth smaller than the above and reaching the p-type first semiconductor layer, and (c) sequentially forming a p-type first semiconductor layer in the peripheral portion of the mesa stripe region. , An n-type first semiconductor layer and a p-type first semiconductor layer are sequentially buried and grown, and a second semiconductor layer is formed on the p-type first semiconductor layer above the mask. And (d) burying the entire mesa stripe including the mesa stripe with an n-type first semiconductor layer after removing the mask, and a method of manufacturing a p-type substrate-embedded semiconductor laser. 10. A p-type clad layer, an active layer, and an n-layer on a p-type semiconductor substrate with a buffer layer made of a p-type semiconductor interposed therebetween.
A mesa stripe region formed of a clad layer, the region extending from the side of the mesa stripe region to the buffer layer is buried with a buried layer made of a p-type semiconductor, and an n-type current block layer and a p-type layer are formed on the buried layer. A current blocking layer is sequentially formed, and a recombination layer having a bandgap wavelength shorter than the oscillation wavelength of the laser is provided on the p-type current blocking layer and separated from the active layer by a predetermined distance. P-type substrate-embedded semiconductor laser covered with a buried layer. 11. The active layer is a multiple quantization well (MQW).
11. The p-type substrate-embedded semiconductor laser according to claim 10, which has a structure.