JPS6077473A - Semiconductor light emitting element and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a light emitting element having high external quantum efficiency by forming an N type AlGaAs first clad layer, an AlGaAs active layer, a P type AlGaAs second clad layer defined in all compositions on an N type GaAs substrate, and forming a reflecting film layer made of alternate laminates of N type AlGaAs layers of different compositions in the first clad layer. CONSTITUTION:An N type AlzGa1-zAs first clad layer 2, an AlpGa1-pAs active layer 3, a P type AlqGa1-qAs second clad layer 4 are laminated on an N type GaAs substrate 1 to form a semiconductor light emitting element. With this construction, a reflection preventive layer 9 made of alternate laminates of N type AlxGa1-xAs layer 91 and N type AlyGa1-yAs layer 92 is formed on the side faced with the substrate 1 of the layer 2. Here, p, q, x, y, z<1, p<q, xnot equal to y, p<z, x>=p, y>=p and the compositions are defined. Thus, the absorption of the light emitting light beam to the substrate is prevented, thereby obtaining high light emitting intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for depositing n(* or p)-AlxGa+-z on a 11(or p)-GaAs substrate as necessary.
As layer (referred to as first cladding layer) and AlyGa, -y
As layer (referred to as active layer), 1] (or n) Alz
The present invention relates to a semiconductor light emitting device formed with a Ga, -zAs layer (referred to as a second cladding layer) and a method for manufacturing the same.

FIG. 1 is a structural sectional view of a conventional semiconductor light emitting device. +51 In the diagram, the code 1 is 11 (or p) - G
a A s substrate, 2 is 11 (or 1+) -A 1z
Gat-zAs layer (referred to as first crand layer), 3 to 1
pGa1-pAs layer (referred to as active layer), 4 is 1) (or n)-AlqGal-qAs layer (referred to as second cladding layer), 5 is 1) (or n+)-GaAs layer, 6 is T
The i layer, 7 is an Au layer, and 8 is AuGeJfl. Since such a semiconductor light emitting device uses a high or p)-GaAs substrate, most of the emitted light is absorbed by this substrate, resulting in a low external quantum efficiency.

An object of the present invention is to prevent the emitted light from being absorbed by the substrate and to obtain a high external quantum efficiency as a high-brightness light-emitting device.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings. FIG. 2 is a structural sectional view of this embodiment, and parts corresponding to those in FIG. 1 are given the same reference numerals. In FIG. 2, 1 is a ++ (or p)-GaAs substrate, 2 is a ++ (
or p) -AlzGa, -zAs layer (referred to as first cladding layer). 3 is AlpGa+-pAs layer (referred to as active layer, where p<z,), 4 is 1) (or n)
-AlqGal-qAs layer (referred to as second cladding layer, p<q, p+q<1), 5 is 1)÷(or n+) -GaAs layer, 6 is Ti layer, 7 is Au layer, 8 is AuGe layer It is.

9 is the 11 (or p) C; between the aAs substrate 1 and the active layer 3, the n (or p) -A 1xGa1-x
As layer 91 and mouth (or p)-AlxGa1-yAs
Layer 92 (where x, y<1, X%y, x≧1], y≧
This is a reflective film layer formed by laminating multiple layers of (p) and (p) alternately. The thickness of each layer 91 and 92 constituting this reflective film layer 9 is set to λ/4n (where λ is the center emission wavelength and ++ is the refractive index). When a large number of layers in which the compositions of A1 are different from each other and the film thickness is set to λ/411 are laminated in this way, wavelengths in a certain range around the central emission wavelength λ are selectively reflected. Therefore, such a reflective film layer 9
In the semiconductor light emitting device having the above structure, the emitted light is no longer absorbed by the substrate 1, the external quantum efficiency is improved, and light can be emitted with extremely high brightness. Figure 3 shows the reflectance on the vertical axis and the wavelength on the horizontal axis.
The composition in the layer is X20.35 (refractive index ++1=3.6
), a film thickness of 450 angstroms, x=0.7 (refractive index n2=3.3), and a film thickness of 490 angstroms, for a total of 49 layers, is a diagram showing the reflectance at outside wavelengths.

As is clear from FIG. 3, the reflectance is about 94% when the wavelength is λ or 663n+n. As described above, according to this example, a semiconductor light emitting device with extremely high brightness can be obtained.

As described above, according to the present invention, 11 (or p)-AlzGa, -zA
s layer (referred to as first cladding layer) and AlpGa+-pA
s layer (referred to as active layer) and 1] (or n)-AlxG
In a semiconductor light emitting device in which an a1-qAs layer (referred to as a second cladding layer) is formed, in the first cladding layer,
++(or p)-AlxGa1-xAs layer and 11(
or p)-AlyGa1-yAs layer (s l)
+Q'+X+V+z<1, p<q, x≠y.

Since a reflective film layer is formed by alternately laminating multiple layers of p<z, x≧p, y≧1)), the emitted light is not absorbed by the substrate, and a high external quantum efficiency can be achieved as a high brightness light emitting device. can get

[Brief explanation of drawings]

FIG. 1 is a structural sectional view of a conventional example, FIG. 2 is a structural sectional view of an embodiment of the present invention, and FIG. 3 is a diagram showing the reflectance of the reflective film according to the embodiment with respect to wavelength. 1., n (or p)-GaAs substrate, 2. ,,n(
Mas+t++)-8I+ρ+ -＾-1a/IdV
i /-2le limit 1 +'11. /n-doped or 1) or n-AlpGa+-pAs layer (active layer), 4
．． , , p (or n) -A 1qGa+ -qA
S layer (second cladding layer), 50. , I]+(or II
+)-G a A S layer, 6. , , Ti layer, 7. ,,A
u layer, 8°, AuGe layer, applicant: ROHM Co., Ltd. agent, patent attorney: Kazuhide Okaguchi]

Claims (1)

[Claims] An AlzGal-zAs layer (referred to as a first cladding layer),
In a semiconductor light emitting device in which an AlpGal-pAs layer (referred to as an active layer) and p(or 11)-AIqGa+-qAs/i (referred to as a second cladding layer) are formed, 11( or p) -A 1xG
al-zAs layer and mouth (or p)-A 1yGa1-
yAs layer (I)+Q+x+y17. <Semiconductor light emitting device formed by forming a reflective film layer formed by stacking layers. In a method for manufacturing a semiconductor light emitting device by forming a pcal-pAs layer (referred to as an active layer) and an I) (or n)-AIqGa+-qAs layer (referred to as a second cladding layer), the former As layer and the n( or p)-AlyGa+-yAs
layer (however, DIQIXIFI2<1% +1<Q
%IT<Z+X? 'y, X≧p, y≧p) are alternately stacked in multiple layers to form a reflective film layer.