JPH07335118A - Manufacture of semiconductor device having semiconductor layer using edge surface as etching surface - Google Patents

Abstract

PURPOSE:To provide a manufacturing process of a semiconductor device having a plane edge surface by using the edge surface by regrowth as a etching surface of a single semiconductor. CONSTITUTION:The manufacturing process of a semiconductor device having a semiconductor layer formed by etching the edge surface is provided. Epitaxial layers 2-10 are formed on a board 1, this multilayer semiconductor layer is etched to form an edge, the edge is covered with a regrowth layer 11, then the regrowth layer is etched to form the edge surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface.

[0002]

2. Description of the Related Art Heretofore, various semiconductor devices such as a semiconductor laser, an optical modulator, and a waveguide having a semiconductor layer whose end face is formed by dry or wet etching have been proposed. According to such a semiconductor device, since the end face can be formed without cleaving together with the semiconductor substrate, the thickness and size of the semiconductor substrate can be arbitrarily set, and other devices on the same semiconductor substrate can be set. It becomes possible to monolithically integrate with, and to construct an optoelectronic integrated circuit and an optical integrated circuit. By the way, in a conventional method of manufacturing a semiconductor device having a semiconductor layer whose end face is formed by etching, a method of etching a semiconductor layer having a multi-layer structure by a single etching method has been adopted.

[0003]

In the conventional method of manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface, a semiconductor layer having a multi-layered structure is used to form a semiconductor device having an end face as an etching surface. In the method of etching a single layer by a single etching method, it has been a problem that it is difficult to obtain a flat etched surface because the etching conditions of the layers forming the semiconductor device are different. Therefore, for example, in the case of a laser having an etching surface as a mirror surface, there is a drawback that the reflectance of the mirror is lowered, the reflection loss is increased, and the laser characteristics are deteriorated. Further, when the layer structure and composition of the semiconductor device are different, the etching conditions are different, so it is necessary to optimize the etching conditions for different semiconductor devices each time, and a good etching surface with good reproducibility can be obtained. It had the drawback of being difficult.

Further, especially in a GaAs laser, the end face has an important meaning for reliability. It causes a temperature rise due to non-radiative recombination via surface levels existing on the surface of the semiconductor crystal. Due to this temperature increase, the band gap is reduced, and feedback is applied to further increase the temperature. For this reason, melting of the end face is induced and the optical output is reduced, causing irreversible destruction, that is, optical damage destruction COD (Catastrophic Optical Damage)
Is a problematic part. The surface level of the end face that causes the optical damage is often due to damage at the time of etching, but it is difficult to satisfy both the etching condition with less damage and the etching condition with good flatness. The present invention has been proposed to remedy the above-mentioned drawbacks, and an object thereof is to provide a novel method for manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface, which does not have the above-mentioned drawbacks.

[0005]

In order to achieve the above object, (1) the present invention is a method for manufacturing a semiconductor device having a semiconductor layer whose end face is formed by etching, wherein at least two or more multilayer semiconductor layers are etched. A first step of forming an end surface by etching, a second step of covering the end surface with a single semiconductor layer by regrowth, and a third step of forming the end surface by etching the single semiconductor layer. A feature of the invention is a method of manufacturing a semiconductor device having a semiconductor layer having an end surface including and as an etching surface. (2) In the invention according to (1), the single semiconductor layer is formed of InG.
A feature of the present invention is a method for manufacturing a semiconductor device having a semiconductor layer having an end surface that is an aP layer as an etching surface. (3) In the invention according to (1), the single semiconductor layer is formed of InP.
A feature of the invention is a method of manufacturing a semiconductor device having a semiconductor layer having an end surface serving as a layer as an etching surface.

[0006]

According to the method of manufacturing a semiconductor device having a semiconductor layer having an end surface as an etching surface according to the present invention, when forming a semiconductor layer having an end surface as an etching surface, a multi-layer structure is used as in the conventional method of manufacturing a semiconductor device. The first semiconductor layer does not have to be etched by a single etching method.
Since the end facet is formed by etching the single semiconductor layer covering the etching face formed in the step of 1, the semiconductor device having the semiconductor layer whose end face is the etching face is accompanied by the conventional drawbacks. It can be easily manufactured without. Further, in the method of manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface according to the present invention, the regrown single semiconductor layer which is the etched portion is made of a crystalline material having a large band gap that does not absorb the laser oscillation wavelength. Since a (window structure) is possible, it is possible to provide a semiconductor device that is less likely to be deteriorated by the optical damage destruction COD of the end face.

[0007]

EXAMPLES Next, examples of the present invention will be described. (Embodiment 1) FIG. 1 is a sectional view (resonator direction) of a laser according to Embodiment 1 of the present invention. In the figure, 1 is n ⁺ -GaA
s substrate, 2 n-GaAs buffer layer, 3 n-AlG
aAs clad layer, 4 and 8 are AlGaAs guide layers, 5 and 7 are AlGaAs SCH layers, and 6 is InGa
As strained quantum well active layer, 9 p-AlGaAs cladding layer, 10 p ⁺ -GaAs cap layer, 11 AlGa
It is an As regrown layer. The process for realizing this structure is shown in FIG. First, an epitaxial crystal growth apparatus (M
OCVD method: metal-organic vapor phase epitaxy apparatus or MBE method:
The epitaxial layers 2 to 10 are grown by the molecular beam epitaxy method. In the MOVPE method, trimethylindium (TMI), triethylgallium (TEG), trimethylaluminum (TMA), arsine (AsH ₃ ) are used as raw materials for semiconductor thin film growth, and selenium sulfide (H ₂ Se) and p-type are used as n-type dopants. Diethyl zinc (DEZn) was used as a dopant. The epitaxial growth temperature is about 700 ° C., the growth pressure is about 0.1 atm, and the carrier gas is hydrogen. In the MBE method, metallic gallium (Ga), indium (In), aluminum (Al), and arsenic (As solid) are used as raw materials, silicon (Si) is used as an n-type dopant, and zinc (Zn) is used as a p-type dopant.
Was used. The epitaxial growth temperature is about 650 ° C. and the growth pressure is about 10 ⁻⁵ Torr.

Next, in order to form an AlGaAs regrowth layer, etching is performed to each resonator pitch with a desired stripe width to a depth across the active layer [FIG. 5 (a)]. After that, the AlGaAs regrown layer 11 is grown [FIG.
(B)]. The growth temperature is about 700 ° C. At this time S
An insulating film such as iO ₂ or Si ₃ N ₄ is used as an etching mask, and further used as a selective growth mask during regrowth. After regrowth, contact layer 10 and cladding layer 9
Is processed to form a ridge having a width of about 1.5 to 3 μm. For that purpose, patterning is performed by photolithography, and using this as a mask, 10 or 9 layers are etched by wet or dry etching. The depth is determined in consideration of the transverse mode, and the guide layer 8 may be etched in some cases. Next, etching for forming the mirror end surface is performed.
In this case, only the AlGaAs regrown layer 11 is etched by forming a mask. For that purpose, patterning is performed by photolithography, and using this as a mask, 11 layers are etched by wet or dry etching (FIG. 5C). The depth is determined by taking the spot size into consideration. After forming the ridge and the mirror end face, peel off the mask,
As shown in FIG. 2, the insulating film 12 (Si
O ₂ etc.) is formed on the entire surface and SiO ₂ on the ridge is etched off, and then Cr / Au or Ti / Pt / A
A p electrode 13 such as u and an n electrode 14 such as AuGeNi are formed. After that, ohmic sintering is performed to form an electrode portion. FIG. 2 shows a structural diagram (cross section perpendicular to the cavity direction) of the laser of Example 1 of the present invention.

(Embodiment 2) The same laser as in Embodiment 1 can be realized when the regrown layer 11 is an InGaP layer. The epitaxial growth and manufacturing process can be performed in the same procedure as in the first embodiment. In this case, the regrowth temperature is lower than that in Example 1 (600 ° C.).
Can be realized without being affected by deterioration due to diffusion in the semiconductor during regrowth.

(Third Embodiment) FIG. 3 shows a perspective view of a laser according to a third embodiment of the present invention. In the figure, 15 is n ⁺ -InP
Substrate, 16 n-InP buffer layer, 17 and 19 InGaAsP guide layer, 18 InGaAs / InG
aAsP quantum well active layer, 20 p-InP clad layer, 21 p ⁺ -InGaAs cap layer, 22 In
It is a P regrowth layer. To realize this structure, first,
Epitaxial layers 16 to 21 are grown by an epitaxial crystal growth apparatus (MOCVD method: metal organic chemical vapor deposition apparatus or MBE method: molecular beam epitaxy method). In the MOVPE method, TMI, TEG, phosphine (PH ₃ ) and AsH ₃ are used as raw materials for semiconductor thin film growth.
H ₂ Se was used as the n-type dopant and DEZn was used as the p-type dopant. Epitaxial growth temperature is about 65
At 0 ° C., the growth pressure is about 0.1 atm, and the carrier gas is hydrogen. In the MBE method, metallic Ga, In, PH ₃ are used as raw materials.
And AsH ₃ , Si was used as the n-type dopant, and Zn was used as the p-type dopant. The epitaxial growth temperature is about 500 ° C. and the growth pressure is about 10 ⁻⁵ Torr.

Next, in order to form an InP regrowth layer, etching is performed to a depth across the active layer while leaving a ridge portion which becomes a resonator at an arbitrary interval. After that, iron dope I
Grow the nP regrown layer. At this time, SiO ₂ or S
An insulating film such as i ₃ N ₄ is used as an etching mask, and further used as a selective growth mask during regrowth. In this case, the InP regrown layer is not only the end face etching layer but also a buried layer for current constriction and refractive index control. Next, etching for forming the mirror end surface is performed. In this case, the InP regrowth layer 22, the substrate 15, and the buffer layer 16 are etched by the mask. Therefore, patterning is performed by photolithography, and these layers are etched by wet or dry etching using this as a mask. The depth is determined by taking the spot size into consideration. After forming the mirror end face, the mask is peeled off, and the p electrode 2 of Cr / Au or Ti / Pt / Au is formed.
3. An n-electrode 24 made of AuGeNi or the like is formed. afterwards,
Ohmic sintering is performed to form an electrode part. Figure 4
The structural drawing of the laser of Example 3 of the present invention manufactured through the above steps is shown.

[0012]

According to the method of manufacturing a semiconductor device having a semiconductor layer having an end surface as an etching surface according to the present invention, in forming a semiconductor layer having an end surface as an etching surface,
A flat end face can be obtained by etching a single semiconductor layer by re-growing the end face without etching the semiconductor layer having a multi-layer structure by a single etching method as in the conventional semiconductor device manufacturing method. The characteristics of the laser were comparable to those of the cleaved end face. Further, in the method of manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface according to the present invention, the regrown single semiconductor layer which is the etched portion is made of a crystalline material having a large band gap that does not absorb the laser oscillation wavelength. (Wind structure), it is possible to provide a semiconductor device that is less likely to deteriorate due to optical damage destruction COD of the end face.

[Brief description of drawings]

FIG. 1 is a diagram showing a laser epitaxial cross section of Example 1 of a method for manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface according to the present invention.

FIG. 2 is a diagram showing a laser structure of Example 1 of a method for manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface according to the present invention.

FIG. 3 is a diagram showing a perspective view of a laser according to a third embodiment of a method of manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface according to the present invention.

FIG. 4 is a perspective view showing a laser structure of Example 3 of a method for manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface according to the present invention.

FIG. 5 is a diagram showing steps of a method for manufacturing a semiconductor device having a semiconductor layer having an end surface as an etching surface according to the present invention. (A), (b), (c) shows each process.

[Explanation of symbols]

1 n ⁺ -GaAs substrate 2 n-GaAs buffer layer 3 n-AlGaAs clad layer 4 AlGaAs guide layer 5 AlGaAsSCH layer 6 InGaAs strained quantum well active layer 7 AlGaAsSCH layer 8 AlGaAs guide layer 9 p-AlGaAs clad layer 10 p ⁺ -GaAs Cap layer 11 AlGaAs regrowth layer 12 Insulating film 13 p electrode 14 n electrode 15 n ⁺ -InP substrate 16 n-InP buffer layer 17 InGaAsP guide layer 18 InGaAs / InGaAsP quantum well active layer 19 InGaAsP guide layer 20 p-InP clad layer 21 p ⁺ -InGaAs layer 22 InP regrowth layer 23 p electrode 24 n electrode

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Eiichi Kuramochi 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. A method of manufacturing a semiconductor device having a semiconductor layer having an end face formed by etching, comprising a first step of forming an end face by etching at least two or more multi-layer semiconductor layers, and regrowth of the end face. A semiconductor having a semiconductor layer having an end surface as an etching surface, which includes a second step of covering with a single semiconductor layer and a third step of forming an end surface by etching the single semiconductor layer. How to make the device. 2. The single semiconductor layer according to claim 1,
A method of manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface, which is a GaP layer. 3. The single semiconductor layer according to claim 1, wherein the single semiconductor layer is In.
A method of manufacturing a semiconductor device having a semiconductor layer having an end face as an etching surface, which is a P layer.