JPS632394A - Manufacture of semiconductor light-emitting device - Google Patents

Abstract

PURPOSE:To control diffusion depth in the lateral direction with high accuracy by diffusing the lateral direction from the end surface of a semiconductor layer as the direction of diffusion in the control of the width of an active layer being controlled by lateral diffusion vertical in the direction of diffusion in a current injection type semiconductor laser. CONSTITUTION:Active layers are laminated alternately onto an Si-GaAs substrate 11, and a photo-resist 10 is formed as an etching mask for shaping end surfaces by using normal lithography. Both end surfaces approximately vertical to each layer are shaped through reactive ion etching. Both end surfaces are coated through sputtering, and an SiO2 layer is applied onto the whole surface of the substrate as an introduction-resistant layer for an impurity. Ar ion beams are projected from the oblique lateral direction so as to be made approximately vertical to the end surfaces to etch an SiO2 layer 4, and only one end surface is exposed. Si is diffused from the end surface to shape an n-type region 5, and the SiO2 layer 4 is removed. Likewise, Zn is diffused from the end surface, employing an SiO2 layer 6 exposed to the other surface as a mask and a p-type region 7 is formed on the other side, and the SiO2 layer 6 is gotten rid of.

Description

[Detailed Description of the Invention] [Summary] In order to improve the controllability of the shape and depth of the diffusion front when forming a lateral (parallel to the substrate) injection laser, only the end face is exposed and the rest is exposed. A method is proposed in which impurities are introduced from the end face using a mask with an introduction layer.

[Industrial application field]

The present invention relates to a method of manufacturing a semiconductor light emitting device, and more particularly to a method of manufacturing a semiconductor light emitting device with improved precision in forming a lateral injection laser.

In a current injection semiconductor laser, if current can be injected from the side while confining light and current, the p-side and n-side picture electrodes can be formed on the substrate surface, which simplifies the manufacturing process. Optoelectronic integrated circuit (OEIC, Qp
toelectronic IntegratedCi
rcuit).

(Prior art) As a lateral injection laser, TJS (Trans
-verse Junction 5tripe) laser, but its layer structure is not compatible with electronic devices, so
It could not be said to be effective for 0EIC.

FIG. 2 is a sectional view showing an example of a TJS laser.

In the figure, a semi-insulating (SI)-GaAs substrate (Sub
, ) 21, an n-AlGaAs layer 22, a low GaAs layer 23 serving as an active layer, and an n-AlGaAs layer 224 are grown in sequence, and zinc (Zn) is diffused on one side to form a p-type head region 25.

In the figure, n- between the diffusion front indicated by the dotted line and the p-type head region 25.
GaAs 23 becomes an intrinsic semiconductor and forms an active layer.

The length direction of the active layer is perpendicular to the plane of the paper.

On the p-type head region 25, gold/zinc/gold (Au
/Zn/Au) layer 26, and the n-AlGaAs layer 24 on the surface
Gold/gold germanium (Au/Au
Ge) layer 27 is formed.

In the above layer structure, n-AlGaAs24 on the surface
Field effect transistors (FETs) cannot be optimized and integrated thereon.

Therefore, next, a lateral injection laser employing a layer structure compatible with electronic devices will be described.

FIG. 3 is a cross-sectional view of a lateral injection laser explaining a conventional method step by step.

In FIG. 3 (1), high resistance (HR) -Al o, 5 Gao, l, As layers 1 and AlGaAs/GaA layers alternately stacked as active layers are formed on a 5I-GaAs substrate 11.
Mqw (multilayer quantum well) structure 2 consisting of s layer, HR-
A16. , Ga, , As layers 3 are sequentially grown.

Buttered silicon dioxide (
Using the Si(h) layer 4' as a mask, silicon (
St) is diffused to form an n-type region 5' on one side, and Si0
1 layer 4' is removed.

In FIG. f (2), using the patterned 5iOz layer 6' as a mask, Zn is diffused from the substrate surface to form a p-wall region 7' on the other side, and the 5iQz layer 6' is removed.

During the diffusion process in the n-type region 5' and the p-wall region 7', diffusion also progresses in the lateral direction perpendicular to the diffusion direction, and the MQ sandwiched between the double-headed regions
It becomes difficult to control the width of the W structure 30, that is, the width of the active layer.

[Problem that the invention seeks to solve]

According to the conventional example, control of the width of the active layer is determined by the accuracy of lateral diffusion perpendicular to the diffusion direction, and therefore has extremely low accuracy.

[Means for solving problems]

FIGS. 1(1) to 1(7) are cross-sectional views of a lateral injection laser explaining the method of the present invention step by step.

The above problem can be solved by sequentially stacking a first semiconductor layer 1 of one conductivity type, a second semiconductor layer 2 serving as an active layer, and a third semiconductor layer 3 of one conductivity type, and One end face substantially perpendicular to is exposed, the other part is covered with an introduction-resistant layer 4, impurities of one conductivity type are introduced into each of the semiconductor layers to form a one-conductivity type region 5, and the introduction-resistant layer 4 is removed. Then, the other end face parallel to the one end face is exposed and the other end face is covered with an introduction-resistant layer 6 to introduce impurities of other conductivity type into each of the semiconductor layers, and do not contact the one conductivity type region 5. This is achieved by a method of manufacturing a semiconductor light emitting device including a step of forming a region 7 of a different conductivity type.

[Effect]

In the present invention, the width of the active layer (that is, the pn junction W formed by diffusion), which was controlled in the conventional method by lateral diffusion perpendicular to the diffusion direction, can be controlled in the lateral direction from the end face of the semiconductor layer. This takes advantage of the fact that the lateral diffusion depth can be controlled with high precision by diffusing as

〔Example〕

An embodiment of the present invention will be described with reference to FIG.

In FIG. 1(1), H
R-A16. aGao, 6AS layer (first semiconductor layer) 1, AlGaAs/Ga stacked alternately as active layer
MQ-structure (second semiconductor layer) made of AsN 2, H
R-Ala, aGao, and hAs layers (third semiconductor layer) 3 are grown in sequence.

Next, a photoresist 10 is formed as an etching mask for forming the end face using normal lithography.

Microposit 1300-37 was used as the photoresist.

In FIG. 1(2), the semiconductor layer is etched using boron trichloride (BCl2) decachloride (C12) as an etching gas or by active ion etching (RIE) to form both end faces substantially perpendicular to each layer.

In Fig. 1 (3), a layer with a thickness of 8,000 mm is formed by sputtering to cover both end faces and form an impurity introduction-resistant layer on the entire surface of the substrate.
Deposit the human 5iCh layer 4.

In FIG. 1 (4), using the argon (Ar) ion beam etching method, the SiO□ layer 4 is etched by irradiating the Ar ion beam from the side obliquely so that it is almost perpendicular to the end face, and only one end face is etched. be exposed.

In FIG. 1(5), using the exposed 5ift layer 4 on one end face as a mask, Si is diffused from the end face to form an n-type region 5 on one side, and the SiO□ layer 4 is removed.

Diffusion of Si was carried out at 800°C using a deposited St film as a source.
Perform solid phase diffusion with 2. Dope to a concentration of about 10"cm-".

In FIG. 1 (6), similarly, the exposed Si on the other end surface
Using the Si02 layer 6 as a mask, Zn is diffused from the end face to form a p-type head region 7 on the other side, and then the Si02 layer 6 is removed.

Zn was diffused in a sealed tube using ZnAs as a source.
This is done by heating at 00° C. and doping to a concentration of about 10 cm −’.

In this case as well, the MQ-
The width of the structure 3 becomes the width of the active layer, which is formed to be 1 μm.

An Au/AuGe layer 1 with a thickness of 2700/300 mm is formed as an n-side electrode on the n-type region 5.

This completes the process according to the present invention.

In the embodiment, MQW was used for the active layer, but a single layer structure may also be used instead.

〔Effect of the invention〕

As described above in detail, according to the present invention, in a lateral injection laser, the width of the active layer can be controlled with high precision.

[Brief explanation of drawings]

Figures 1 (1) to (7) are cross-sectional views of a lateral injection laser explaining the method of the present invention step by step; Figure 2 is a cross-sectional view of an example of a TJS laser; and Figure 3 is a cross-sectional view of a conventional method. FIG. 3 is a cross-sectional view of a lateral injection laser explained step by step. In the figure, 1 is HR-Ale, aGao, 6A3 layer, 2 is active layer with MQ-structure, 3 is IIR-Ale, aGao, bAs layer, 4 is impurity introduction resistance layer, SiO□ layer, 5 is n-type 6 is an impurity introduction resistance layer and is a 5iOz layer, 7 is a p-type head region, 8 is a p-side electrode and is an Au/Zn/Au layer, 9 is an n-side electrode and is an Au/AuGe layer, 10 is a resist, and 11 is a resist. 5I-GaAs substrate grass 1 figure leather 3 figures

Claims (1)

[Claims] Formed by sequentially stacking a first semiconductor layer (1) of one conductivity type, a second semiconductor layer (2) serving as an active layer, and a third semiconductor layer (3) of one conductivity type. Then, one conductivity type region (5) is formed by exposing one end face substantially perpendicular to each of the semiconductor layers and covering the rest with an introduction-resistant layer (4), and introducing impurities of one conductivity type into each of the semiconductor layers. Then, the introduction-resistant layer (4) is removed to expose the other end face parallel to the one end face, and the rest is covered with the introduction-resistant layer (6) to introduce impurities of other conductivity type into each of the semiconductor layers. and the other conductivity type region (5) so as not to contact the one conductivity type region (5).
7) A method for manufacturing a semiconductor light emitting device, comprising the step of forming.