JPH01245569A - Gap green light-emitting element and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve the luminous efficiency of the title element without being affected by the crystallizability of an n-type GaP substrate by a method wherein the element is provided with the substrate, an N-type GaPLPE layer formed in a layer thickness deposited at a specified value or higher and 3 layers of an n(1)-type GaPLPE layer, an n(2)-type GaPLPE layer and a p-type GaPLPE layer, which are laminated in this order, and N is added to at least part of the intermediate layer among the above 3 layers. CONSTITUTION:An n-type GaPLPE layer 11 is formed on the upper surface of an n-type GaP substrate 101 in a layer thickness of 70mum or thicker. Moreover, the layer 11 is formed in such a way that its carrier concentration is within a range of 1X10<17>-15X10<17>cm<-3>. 3 layers of an n(1)-type GaPLPE layer 12, an N(2)-type GaPLPE layer 13 and a P-type GaPLPE layer 14 are laminated on the upper surface of the layer 11 in this order. The title element is constituted of the substrate 101, the layer 11 and the laminated layers, which are the GaPLPE layers and respectively have structures of an n(1)-type, an n(2)-type and a p-type, and moreover, N is added to at least part of the layer 13 which is the intermediate layer among these 3 layers. Moreover, each carrier concentration of the above 3 layers is exemplified as an example as follows: The carrier concentrations of the layers 12, 13 and 14 are respectively formed into 2-4X10<17>cm<-3>, 0.5-4X10<16>cm<-3> and 6-40X10<17>cm<-3>. That is, the carrier concentration of the layer 1 3, which is the intermediate layer, is smaller than that of any one of the layers to come into contact to this layer 13.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an epitaxial structure of a GaP light emitting device,
In particular, it is used for GaP green light emitting devices.

(Conventional technology) The structure of a conventional GaP light emitting device is shown in cross section in FIG.

In FIG. 6, 101 is an n-type GaP base Fi (hereinafter referred to as n-GaP substrate, omitting the type), S, D, or S.
an n(1)-GaPLPE layer 102 doped with i and deposited on its upper surface by a liquid epitaxial (hereinafter abbreviated as LPE) method. n■-GaPLP
E layer 10:3. Three p-GaPLPE layers 104 are formed by stacking them in this order. Next, in order to make the thickness of the light emitting element uniform, after lapping, AuGe or AuSx l^uBe was applied to the n-type surface and the p-type surface, respectively.
Alternatively, the n-electrode 105 and the p-electrode 106 are formed by vapor depositing an Au alloy of AuZn, performing heat treatment, and photolithography. Thereafter, it was divided into chips using a blade dicer or the like to obtain GaP green light-emitting tines.

Note that three layers of n/n Ci/p GaP layers 102 and 103 are laminated on the GaP substrate 101.
．． 104 may be a GaP layer of nQ)/p■/p■.

(Problem to be solved by the invention) The luminous efficiency (brightness) of the GaP green light emitting device is as follows (i)
Control of carrier concentration in each epitaxial layer:
o, s x to"~I x 10" cx-3(i
i) Carrier concentration of the substrate wafer (iii) It largely depends on the crystallinity of the substrate wafer.

In particular, the correlation with the crystallinity of the substrate wafer (this will be explained later in this section) is strong.

Etch pit density of epitaxial layer (hereinafter referred to as lE, P,
A correlation diagram between D) and luminescence intensity is shown in FIG.

E, P, and D are indicators regarding crystallinity.

Furthermore, substrate wafers manufactured by the pulling method have various limitations on improving crystallinity, and generally have poor crystallinity. Furthermore, since the crystallinity is even worse in the peripheral area (E, P, and D are large), the emission intensity of the green light emitting element manufactured in this area becomes weak.

As described above, the problem with improving the performance of GaP green light emitting devices is how to use a good substrate wafer. In particular, improving crystallinity around the periphery of the substrate wafer is a major challenge.

By the way, E near the p-n junction of the epitaxial layer,
P and D are crystal defects existing in the substrate, such as D-pi
It is significantly affected by t (deep pit 1) + 5 pit (shallow pit 1), etc. Therefore, E, P of the epitaxial layer,
In order to reduce D, it is necessary to improve the crystallinity of the substrate, but this is highly difficult with current technology. Therefore, it is important to develop a technology to form an epitaxial layer near the p-n junction with good crystallinity without being affected much by the crystallinity of the substrate, in order to improve the luminous efficiency and quality of green light-emitting devices. has become an urgent issue.

An object of the present invention is to provide a structure of a green light-emitting element with high luminous efficiency and a method for manufacturing the same, regardless of the crystallinity of the substrate.

[Structure of the invention]

(Means for Solving the Problem) The present invention relates to a GaP green light emitting device and a method for manufacturing the same.
The GaP green light-emitting device includes an n-GaP substrate grown using a liquid-sealed Czochralski method, and a layer having a thickness of 70. The n-GaPLPE layer deposited above and the n-Ga
Three GaPLPE layers of n(1)/n■/p or n■/p■/p■ formed on the PLPE layer are provided in this order, and at least one of the three layers is provided as an intermediate layer of the three layers. Part N
The manufacturing method includes a step of growing an n-GaP substrate using a liquid-sealed Czochralski method, and a layer thickness of 70 μs on the n-GaP substrate using a liquid epitaxial method. More than n-GaP
a step of depositing and forming an LPE layer; and a step of forming the n-GaPL layer.
Si or T is deposited on the PE layer by liquid epitaxial method.
e is added to form an nO-GaPLPE layer, followed by an N
The nO-GaPLPE layer is formed by adding Zn, and the p-GaPLPE layer is formed by adding Zn.
-GaPLPE layer, and also includes the steps of sequentially growing n-GaPLPE layers using the liquid-sealed Czochralski method.
A step of growing a P substrate and forming an n − layer with a thickness of 70 μm or more on the n-GaP substrate by liquid epitaxial method.
a step of depositing and forming a GaPLPE layer;
By liquid epitaxial method, Si or Te is added onto the aPLPE layer to form an n(υ-GaPLPE layer, and N and C are simultaneously added to form a P(1)-GaPLP[E layer,
Continuously adding Zn to this, p(2) -GaPLEP
This method includes a step of sequentially growing EM and EM.

(Function) Even if the crystallinity of the substrate is poor, this invention can be applied to the substrate and GaP green epitaxial three layers (n■/n■/Panω/P■/
By interposing an n epitaxial layer with good crystallinity between the substrate and the substrate, a green light-emitting element having a structure that is not affected by the crystallinity of the substrate can be obtained.

(Example) Hereinafter, a GaP green light emitting device according to an example of the present invention and a method for manufacturing the same will be explained with reference to the drawings.
A P-green light emitting device is shown in cross-section in FIG. 1a. In FIG. 1a, reference numeral 11 denotes an n-GaPLPE layer formed on the upper surface of the n-GaP substrate 101 to a thickness of 70 μs or more. The layer thickness of this n-GaPLPE [11] was determined based on the table in FIG. 2 showing the correlation between layer thickness and emission intensity. Moreover, this n-GaPLPE layer 11 is
The layer is formed so that the concentration of 1A in the layer is within the range of IX101×1017a++-3.

nO-GaPLP on the upper surface of the n-GaP substrate upper layer 11.
Em12゜nOGaPLPE layer 13. p-GaPLP
The three layers of EM14 are GaPLPE layers laminated in this order, and have a laminated layer with a structure of n / n (2) / p,
Moreover, the nO-GaPLPE layer 13 as the intermediate layer is characterized in that at least a portion thereof is doped with N. Further, the carrier concentration of each of the three layers is, for example, nO-GaPLPE [12 is 2 to 4 × 101101
7C, the nO-GaPLPE layer 13 is 0.5 to 4XIO
“a++-” has 6 to 40 p-GaPLPEW 14
x 10"cs-" respectively. That is, the carrier concentration of the nO-GaPLPE layer 13, which is the fifth intermediate layer, is characterized in that it is lower than any of the layers in contact with it.

Next, in the GaP green light emitting device according to the present invention, as shown in FIG.
O-GaPLPE layer 15. p(]) GaPLPE
Layer 16. p■-GaPLPE layer 17 in this order nα)/
It is composed of laminated layers having a p■/p■ structure. The carrier concentration in each layer is, for example, n-Ga
The PLPE layer 15 is 2 to 4×1011017C, ρ■-
GaPLPE layer is I×4×10”Cjl+-’, p
(2) -G a P L P E layer 17 is 6 to 40
X1017an-'. The features such as the addition of N to these intermediate layers and the lower carrier concentration than any of the layers in contact with these intermediate layers are the same as those of the nQ)/n■/p structure.

In addition, AuGe and p-plane (LPE) are formed on the first surface (substrate) side.
Electrodes 105 and 106 formed with Augg on the layer) side, respectively.
Equipped with.

Next, Ga having the n■/n■/P structure according to the present invention
A method for manufacturing the P green light emitting device (FIG. 1a) will be explained. First, an n-type GaP substrate 101 having a (111) plane and doped with a dopant such as S, Te, or Si is prepared, and an n-GaPLPE layer with a layer thickness of about 120 μs is formed on the phosphorus side. 11 during stratification. For example, in an Ar atmosphere at 1100°C, Ga, Ga
After retaining and dissolving P and a small amount of Te, 2°C/+a
This is achieved by epitaxial growth at a temperature of up to 750° C. while decreasing the temperature at a rate of in. Then,
This n-GaPLPE layer 11 is wrapped so that the thickness of the layer is 1011IIl, and the carrier concentration is set in the range of 1.0 to 15.0 cm''3.

Next, the following G
Three layers of an aP green light emitting device are deposited sequentially in a series of epitaxial growths. For this purpose, an n-GaPLPE layer 11 is deposited, a 1n-type GaP substrate 101 is set in a boat made of quartz parts, and this is heated to 1000° C. in an H2 atmosphere.
Contact with dissolved Ga and GaP,
Add Si or Te and lower the temperature at 2°C/n+in, for example, to 970°C, and form a layer of about 25 μa+ thick nO).
A G a P L P E layer 12 is grown and deposited. Next, an example of 930
The temperature was lowered to
3 is grown and deposited. Furthermore, Zn in an argon atmosphere
The temperature is lowered to, for example, 800° C. while flowing in a gaseous state, and a p-GaPLPE layer 14 having a thickness of about 25 μI is grown and deposited.

Next, in order to make the thickness uniform, Ga of the n-type GaP substrate 10]
surface (principal surface opposite to the adhering surface of the n-GaPLPE layer 11,
Lapping is applied to the lower surface) side, and an AuGe layer is applied to the n-surface side, 9
An AuBe layer is deposited on each side, heat treated and photo-etched to form an ohmic n-electrode 105. p-electrode 106
form.

Furthermore, it is divided into chips using a blade dicer and subjected to surface treatment to obtain a GaP green light emitting device.

Next, regarding the method for manufacturing a GaP green light emitting device having an n■/p■/p■ structure according to the present invention (FIG. 1b), the manufacturing method of the GaP green light emitting device having the n■/n■/p structure will be described. 6. Explaining the differences from the method of n-GaPL
An n-type GaP substrate 101 on which PEWJl was deposited was set in a carbon boat partially incorporating quartz parts.
Ga.

Contact with dissolved GaP, 2°C/min,
The temperature is lowered to, for example, 970℃, and the temperature is reduced to about 25℃.
6. Next, grow and deposit ω-GaPLPIJJ 15.
In a mixed atmosphere of argon, NH1 and C11
and C were added, the temperature was lowered to 930℃, and the temperature was about 15μ.
A layer of P■-GaPLPIJj16 having a thickness of I is grown and deposited.

Furthermore, while flowing Zn gaseously in an argon atmosphere, the temperature was lowered to an example of 800°C, and a pQ-
A GaPLPE layer 17 is grown and deposited. In the subsequent steps, a GaP green light emitting device is used in the same manner as in the production of the GaP green light emitting device having the nQ)/p■/p■ structure.

〔Effect of the invention〕

According to this invention, the influence of the crystallinity of the substrate is improved, and the average luminous efficiency increases by 30 to 50%, as shown in FIG.
It has a remarkable effect.

Next, since the GaP substrate is formed by a pulling-up (LEC) method, there is a problem with the influence of crystallinity, especially in the peripheral area of the substrate6.According to the present invention, this point has been improved, and the variation in luminous efficiency within the substrate has been improved. is significantly improved as shown in FIG.

Incidentally, the variation within the substrate in the luminous efficiency shown in FIG.

[Brief explanation of the drawing]

FIGS. 1a and 1b are cross-sectional views of GaP green light-emitting devices according to examples of the present invention, and FIG. 2 shows the correlation between the n-GaPLPE layer thickness and emission intensity of the GaP green light-emitting device according to the present invention. Figure 3 is a diagram showing the correlation between H, P, D of an n-type GaP substrate and luminescence intensity in GaP green light emission, Figure 4 is a diagram showing the distribution of luminescence intensity, and Figure 5 is a diagram showing the correlation between luminescence intensity. FIG. 6, which is a diagram for explaining variations in luminous intensity within a substrate, is a cross-sectional view of a conventional GaP green light emitting device. 101...n-type GaP substrate 1(1.GaP green light emitting element 11-n-GaPLPE layer 12-n(1)
) GaPLPE layer 13-n■-GaPLPE layer
14-p-GaPLPE layer 15-n■-GaP1
．． PE layer 16- pQ) GaPL, PR layer 17-
pQ-GaPl, PE layer agent Patent attorney Inoue - Male No. 1 Fig. 2 @ Fig. 3 & Production number - Fig. 4 Magic i/& number - Fig. 5 tol: n type (raP substrate toz: le ( 1)-Master PLP 7:ノ,ytos
', rti theory Io9: F Denrin 1oo: Qap green 'ie party search'r Fig. 6

Claims (7)

[Claims] (1) An n-type GaP substrate grown by a liquid-sealed Czochralski method, an n-type GaPLPE layer deposited on the n-type GaP substrate with a layer thickness of 70 μμ or more by a liquid epitaxial method, and the n-type GaPLPE layer It comprises three layers of n(1) type/n(2) type/p type GaPLPE layers formed on top in this order, and at least a part of the intermediate layer of the three layers is doped with N. G characterized by being
aP green light emitting device. (2) an n-type GaP substrate grown by a liquid-sealed Czochralski method, an n-type GaPLPE layer deposited on the n-type GaP substrate to a thickness of 70 μm or more by a liquid epitaxial method, and the n-type GaPLPE layer Each n(1) type/p(1) type/p(2) type GaPL formed on
A GaP green light emitting device comprising three PE layers in this order, and at least a portion of an intermediate layer between the three layers is doped with N. (3) The carrier concentration of the n-type GaPLPE layer in contact with the n-type GaP substrate is 1×10^1^7 to 15×10^1^7c
The GaP green light emitting device according to claim 1 or 2, characterized in that the GaP green light emitting device is in the range of m^-^3. (4) The GaP green light-emitting device according to claim 1 or 2, wherein Te is added as a donor impurity to the n-type GaPLPE layer in contact with the n-type GaP substrate. (5) The GaP green light-emitting device according to claim 1 or 2, wherein the carrier concentration of the three intermediate layers is lower than that of any of the layers in contact with the intermediate layer. (6) A step of growing an n-type GaP substrate using a liquid-sealed Czochralski method, and growing an n-type GaPLPE on the n-type GaP substrate to a layer thickness of 70 μm or more using a liquid epitaxial method.
A first n-type LPE layer is formed by adding Si or Te on the n-type GaPLPE shoulder by a liquid epitaxial method, and a second n-type LPE layer is formed by adding N continuously onto the n-type GaPLPE shoulder by a liquid epitaxial method. A method for manufacturing a GaP green light emitting device, including the steps of sequentially growing an n-type LPE layer and a p-type LPE layer with Zn added thereto. (7) A step of growing an n-type GaP substrate using a liquid-sealed Czochralski method, and growing an n-type GaPLPE on the n-type GaP substrate to a layer thickness of 70 μm or more using a liquid epitaxial method.
A first n-type LPE layer is formed by adding Si or Te on the n-type GaPLPE layer by a liquid epitaxial method, and a first p-type LPE layer is formed by simultaneously adding N and C on the n-type GaPLPE layer. G-type LPE layer, which includes a step of sequentially growing a second p-type LPE layer by adding Zn thereto.
A method for manufacturing an aP green light emitting device.