JPH0476913A - Manufacture of iii-v compound semiconductor element - Google Patents

Abstract

PURPOSE:To suppress the dispersion in luminance in a III-V compound semicon ductor element having the hetrojunction by depositing a III-V three-component compound on a III-V compound semiconductor substrate whose carrier density is kept at 2.0-3.5 X10<19> atom/cm<3> by liquid-base growing. CONSTITUTION:The carrier concentration of a III-V compound semiconductor substrate for epitaxially growing a group III-V compound is limited to 2.0-3.5 X10<19> atom/cm<3>. A GaAs substrate 1 wherein the specified carrier concentra tion is kept is inputted into a reaction tube. After gas substitution, the tempera ture is increased to 900-1,000 deg.C. This state is maintained for 30-120 minutes. A growing source is uniformly dissolved. Then, the temperature is decreased at the constant speed. Growing solution is brought into contact with the sub strate 1 in the order of a (p) type or an (n) type. Liquid-phase epitaxial growing is performed, and a (p)-type GaAlAs layer 2 and an (n)-type GaAlAs layer 3 are deposited. A pellet for a III-V compound semiconductor light emitting element is completed after specified steps. Thus, the dispersion of luminance is decreased to about a half. The element can be utilized in the dot matrix which requires the constant luminance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Industrial Application Field) The present invention relates to a GaAs substrate used for liquid phase epitaxial (EpitaxiaQ) growth of -V group compounds such as GaAQAs; Especially that Chiaria (Ca
r r i ea) suitable for concentration.

(Prior art) Recently, ■-■ group compound semiconductor light-emitting devices equipped with heterojunctions have been widely used, but GaAQAs with a single heterojunction (SingQe) structure is doped with Zn zinc as an impurity ( After liquid phase epitaxial growth of a m-V group compound such as GaAQAs, electrode formation and dicing (D
Generally, pellets (PeQQet) are manufactured through the icing process.

As shown in FIG. 1, this GaAQAs has a p-type GaAQAs layer 2 and a p-type cladding layer n
A type GaAlAs layer 3 is deposited by liquid phase epitaxial growth. The impurity concentration and thickness of each layer differ depending on the model, but as shown in Figure 2,
The GaA-QAs type cladding layer 2 contains zinc (Zn) as a p-type impurity in an amount of 5 to 7×10 17 AtoIlc 113 to suppress the thickness to 20 to 25 μm. On the other hand, the n-type GaAQAs layer 2 stacked here has a concentration of 2×10
It is generally maintained at about 3×10 18 Atom/cm 3 and formed to have a thickness of 30 to 40 μm.

(Problems to be Solved by the Invention) In an m-V group compound semiconductor device equipped with such a heterojunction, brightness is naturally required to be within a certain range, but as shown in FIG. There are major drawbacks,
It is a liquid phase epitaxial process.
It was thought to be caused by.

The present invention was made under these circumstances, and in particular,
The purpose of this invention is to suppress variations in brightness in a ■-v group compound semiconductor element having a heterojunction.

[Structure of the invention] (Means for solving the problem) The carrier concentration is set to 2.0 to 3. ”X 1019Ato
■-V group compound semiconductor substrate held at m/C■3■-
■Method for manufacturing a ■-V group compound semiconductor device characterized by depositing a group ternary compound by liquid phase growth to form a heterojunction (function) When we investigated the variations in brightness in compound semiconductor devices, we found that they can be roughly divided into two types: 1) those caused by the liquid phase epitaxial process, and 2) those caused by the carrier concentration characteristics of the -V group compound semiconductor substrate. Based on this, the present invention has been completed. The background to this is that when we investigated the correlation between carrier concentration, specific resistance, crystal defects, mobility, and brightness in the ■ = V group compound semiconductor substrate, there was no correlation at all for crystal defects, and that for mobility and specific resistance. whereas the correlation is almost weak.

It has been found that there is a clear correlation with respect to the carrier concentration in the ■-■ group compound semiconductor substrate. The object of this investigation was a ■-v group compound semiconductor substrate, ie, a GaAs substrate, in which zinc was diffused as an impurity.

That is, the added amount of zinc, which is the impurity, is 1019Ato
We had assumed that the brightness would increase linearly when increasing on the order of a+/cTA3, but it turned out that the brightness saturates midway through the plan and actually decreases on the vertical axis. The relative brightness is clearly shown in FIG. 3, where the horizontal axis represents the impurity concentration. Of course, the curve shown in FIG. 3 was obtained by fixing the factor of the thickness deposited by the liquid phase epitaxial process, which is related to brightness, to a constant value, and the carrier concentration was 2. ~3. X 1019At
It is clear that a very constant relative brightness is obtained within the range of .ota/cm.sup.2".

Moreover, since multiple light-emitting elements made of ■-■ group compound semiconductors and forming scene group heterojunctions are often arranged in a dot matrix, there is a demand for products that exhibit a constant relative brightness. strongly demanded by people. From this point of view, it has been found that the manufacturing method of liquid-phase epitaxial growth of a ■-V group compound on a ■-V group compound semiconductor substrate having its own carrier concentration is extremely practical. The present invention was completed based on such knowledge, and the carrier concentration of the ■-V group compound semiconductor substrate on which the ■-V group compound is grown by liquid phase epitaxial growth is 2.
~3. X 10 AtoIIlom 3i:
It is limited.

The thickness of the n-type ■-■ group compound liquid phase epitaxially grown layer, that is, the Zn-containing GaAlAs layer is 20 to 25 μm, and the carrier concentration is approximately 5 to 7×1. O17AtoIl/c
rA3, and the thickness of the n-type ■-V group compound liquid phase epitaxial growth layer, that is, the Te-containing GaAlAs layer is 30 to 4.
At 0μm, the carrier concentration is 2X 1017 to 3x1018
Maintain approximately ^to11/cα3.

(Example) An example of the present invention, that is, a ■-v group compound semiconductor light emitting device is shown below, and its structure is the same as the pellet structure shown in FIG. Group compound liquid phase epitaxial growth layer such as p-type GaAlA
A single heterojunction is formed by depositing an s layer 2 and an n-type GaAQAs layer 3. The carrier concentration and thickness of each layer in this example are summarized in Table 1 below.

(Left below) When a ■-V group compound semiconductor light-emitting device was formed using pellets in which a single heterojunction was formed in this example, a product with uniform brightness was obtained and it became possible to use it in a dot matrix. Ta.

To carry out the above example, a GaAs substrate 1 with a predetermined carrier concentration maintained is placed in a reaction tube, gas is replaced (evacuated if necessary), the temperature is raised to 900°C to 1000°C, and the temperature is raised to 30°C to 1000°C. Hold for 120 minutes. As a result, the growth source (Sou) filled in the growth solution installed integrally with the reaction tube.
rce) and then at a constant rate of 0.3-2
．． After depositing a p-type GaAQAs layer 2 and an n-type GaAQAs layer 3 by performing liquid phase epitaxial growth by bringing p-type or n-type growth solutions into contact with the GaAs substrate 1 in this order while lowering the temperature at 0° C./min, A pellet for an m-v group compound semiconductor light emitting device is completed through necessary electrode forming steps and dicing steps.

[Effects of the Invention] As described above, the method for manufacturing a ■-V group compound semiconductor device according to the method of the present invention is different from the prior art shown in FIG. 4a, and as shown in FIG. Since it has been reduced to about half, it has become possible to use it for Todd matrices that require constant brightness.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of a conventional ■-V group compound semiconductor light-emitting device, and FIG. 2 is a diagram showing the relationship between impurity concentration and thickness of each part of the conventional ■-V group compound semiconductor light-emitting device. Figure 3 is a curve diagram showing the relationship between the carrier concentration and relative brightness of the ■-V group compound substrate used in the ■-V group compound semiconductor light emitting device according to the present invention, and Figure 4 aSb is the m-V group compound semiconductor light emitting device. FIG. 3 is a diagram comparing the variation in brightness obtained by the elements with the prior art and the present invention. 1: III-V group compound semiconductor substrate, 2: III-V group compound semiconductor p-type GaAQAs layer, 3: DI-V group compound semiconductor n-type GaAQAs layer. Agent Patent Attorney Nori Ogo Figure 1 X3 (1, I”) Figure

Claims (1)

[Claims] The carrier concentration was set to 2. ＾0～3. ＾5×10＾1＾9At
Manufacture of a III-V compound semiconductor device characterized by depositing a III-V ternary compound by liquid phase growth on a III-V compound semiconductor substrate held at 0m/cm^3 to form a heterojunction. Method