JPS6017976A - Semiconductor light emitting device - Google Patents

Abstract

PURPOSE:To oscillate monochromatic lights of different wavelengths by matching the period of a diffraction grating to the band gap energy of an active layer, thereby forming a plurality of stripes at the prescribed interval. CONSTITUTION:An InGaAsP [Eg(x)] active layer 2 formed on an N type InP substrate is formed to distribute its band gap energy in x direction, and an interfering pattern 4 is formed and exposed on a P type InGaAs photoguide layer 3 formed thereon. The spread of the period of this pattern 4 is synchronized with Eg(x) of the layer 2. Then, a buried hetero strip 6 is formed. Thereafter, a P type InP layer 7, an N type InP layer 8, a P type InP layer 9 are grown, a P type GaAP layer 10 is eventually formed, the N type side substrate is polished in the prescribed thickness, a P type electrode metal layer 11 is then formed. Subsequently, a mesa etching for isolating one laser is performed, an N type side is then formed, and cleaved in an array shape. Thus, a light emitting device which can produce a laser light having excellent monochromatic property over many wavelength can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device capable of obtaining Lede light with excellent monochromaticity over multiple wavelengths.

Technical Background Lasers differ from ordinary light in that they have different wavelengths and phases (space and time).
This is so-called coherent light. Characteristics of laser light include coherence, monochromaticity, directivity, and high intensity. DFB (Dist
rebutted FeedBack ) and DBR (D
lgtributed BraggReflectio
n) There is a lede.

Conventional technology and problems Conventionally, the above-mentioned DFB and DB which have excellent monochromaticity and are A lede
Some devices that emit R light have a diffraction grating formed on a light guide layer provided close to an active layer formed on a substrate, but it is monochromatic in the range of 1.2 to 1.55 μm, for example. There was no superior laser array light emitting device. To form such a laser array, it is necessary to change the period of the diffraction grating within the plane of the wafer and to change the composition of the active layer accordingly. However, it is difficult to use conventional techniques such as TPG, VPE growth method, and interference optical system, and it has not been possible to realize such a multi-wavelength monochromatic laser array.

In view of the drawbacks that exceed the objectives of the invention, an object of the present invention is to provide a semiconductor device that can obtain laser light with excellent monochromaticity over multiple wavelengths.

Structure of the Invention The object of the present invention is to provide an active layer having various band gap energies on a substrate, and a light beam provided in close proximity to the active layer and in which the band gap energy of the active layer and the period of a diffraction grating are synchronized. This is achieved by a semiconductor light emitting device characterized in that a semiconductor laser array including a guide layer has at least two or more striped structures at regular intervals. explain.

1 to 4 are schematic perspective views for explaining one embodiment of the present invention.

As shown in FIG. 1, on an n-type indium phosphide substrate 1 with a thickness of about 0.2 μm, indium gallium arsenide phosphide (hereinafter referred to as (written as InGaAgP)
(Eg(x)) An active layer is formed so that its bandgap energy is distributed in the X direction, and then the In]a
P-type indium gallium arsenide phosphide (hereinafter p-InGaAsP
) (Kg'> Eg(x)) A light guide layer is continuously grown to a thickness of 0.2 to 0.3 μm by the MBg method.

Next, as shown in FIG.
For example, a photoresist is applied thereon, and an interference pattern 4 is formed and exposed using a laser beam. When forming this interference glossy turn 4, it is possible to obtain a pattern as shown in Fig. 2 by tilting the substrate. Equivalent wavelength m: Any integer. Then, etching is performed using Br2-CH30H using the SIO□ film (not shown) as a mask.
H8 (embedded hetero stripe) 6 is formed (FIG. 3).

Next, it was grown to a thickness of 1μ by liquid phase epitaxial growth.

p-type InP layer 7, thickness I Jim, n-type InP layer 7, p
The mInP layer 9 is grown continuously, and finally the p-type InG
After forming an aAsP layer 10 and polishing the n-side substrate to a thickness of 100 μm, a P electrode metal Tl/Pt/Au layer 11 is formed, and mesa etching is performed to separate the n and losers.
After forming the AuGe/Ni electrode on the 2-2n side, it is cleaved into an array (FIG. 4).

In this way, a novel light emitting device according to the present invention is formed. In Fig. 4, the lengths of L, L, and L3 are 200 to 300 μm/1 piece (however, 1 piece means 1 stripe), 100 μm, and 200 to 300 μm, respectively.
It is. The light emitting device shown in FIG.
Since a plurality of stripes are formed at regular intervals, an InP substrate is used in the different branch inventions, but a GaAs substrate or the like may also be used.

Further, in order to perform the interference/arm turn (FIG. 2) formed in Example 1 with higher precision, it is preferable to use the EB exposure to form a step shape as shown in FIG. 5. In FIG. 2, a indicates a region with the same period.

As described in detail, according to the present invention, laser light with excellent monochromaticity can be obtained over multiple wavelengths.

[Brief explanation of drawings]

1 to 4 are schematic perspective views for explaining one embodiment of the present invention, and FIG. 5 shows another embodiment of the structure shown in FIG. 2. 1- n-type InP substrate, 2- InGaAsP (Eg
(x)) Active layer, 3-InGaAsP (Bg')
gg(x)) Light guide layer, 4...interference no'? Turn, 5... Diffraction grating, 6... Stripe, 7.9・p
type InP layer, 8-p type InP layer, 10 ・P-InGa
AsP layer, 11--metal electrode. Hunger Figure 4 351-

Claims (1)

[Claims] 1. An active layer having a typical bandgap energy on a substrate, and a light guide layer provided close to the active layer and having the bandgap energy of the active layer and the period of the diffraction grating synchronized. 1. A semiconductor light emitting device, wherein a semiconductor laser array includes at least two striped structures at regular intervals.