JPS5864074A - Sic blue light emitting element - Google Patents

Abstract

PURPOSE:To obtain an SiC blue light emitting element having light emitting property and low contacting resistance with an electroce by composing an n type 6H-SiC substrate, the first p type layer having Al as p type impurity accumulated on the substrate and the second p type layer containing more Al then the first layer. CONSTITUTION:Si and Al of 2-5atm% to Si are filled in a crucible 13, and are heated and molten with a high frequency coil 12. The temperature of the molten liquid 16 of the Si and Al at this time is 1,600-1,650 deg.C, and Ar gas is used as atmospheric gas. Since the quartz reaction tube 11 tends to thermally deform at this temperature, it is preferred to provide cooling means for cooling only the tube 11. Then, an n type 6H-SiC substrate 1 mounted at the end of the substrate holder 17 is dipped and held in the liquid 16, thereby forming the first p type layer 2 of 510mum thick with 1-3X18/cm<2> of Al density. Further, Al is further added in the state that the substrate 1 is dipped in the liquid 16, thereby forming the second p type layer 3. In this case, the Al density is preferably more than 1-3X10<19>/cm<2>, and it is important to improve the ohmic characteristic.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a SIC (silicon carbide) blue light emitting device.

Currently, visible light-emitting elements capable of emitting red, green, yellow, and orange light are in practical use. Furthermore, Saiyu has developed a multicolor light-emitting element in which a single light-emitting element can sequentially emit light from red to green, and is now being put into practical use. However, although blue light emitting elements that emit blue, which is one of the three primary colors of light, have been studied for a long time, they have not yet reached a stage where they can be put to practical use.

The material of the blue light emitting element is 81C, Gal.

Two-layer B., ZnB, etc. are listed.

Among them, BIC exhibits high injection efficiency, allows formation of P-n junctions with comparatively low injection efficiency, and 4H@xagonal type SIC (hereinafter referred to as 6-jtc) is approximately 3.
It is considered promising because it has a narrow forbidden band of V. When obtaining a P-n junction, P
As a type impurity, Al(
aluminum rim) is adopted.

However, the characteristics of the P-type layer vary greatly depending on the aluminum addition device used for the deposition.If the aluminum concentration in the P-type layer is about 1 to S x 10"/at, crystallinity and luminescence will decrease. Although the properties are good, the ohmic properties are deteriorated and the contact resistance is high.Also, if the aluminum wire concentration is higher than the above value, the ohmic properties are good, but the crystallinity is poor. There was a problem.

The present invention was made in view of the above-mentioned melting point.
An explanation will be given regarding the embodiment.

FIG. 1 shows an embodiment of the SIC blue light emitting device of the present invention, (1) is an n-type, 6l-81C4 board, (2) is an ff1M
As an impurity deposited on the plate (1), P-type 6 containing 5L
The first P type layer is composed of 1-810, and the t2J of the first r type layer is 1~! It is desirable to have a mulliconcentration of about IX 10"/ed, in which case the crystallinity is good and the hole mobility is 10 to 15"/ma sea, which shows excellent light emission characteristics. Also, the thickness of the first P-type layer (2) should be 5 to 10 μm thick from the viewpoint of the light emission mechanism!
Delicious. (3) is the P deposited on the upper E 1st layer (2).
In the 27th type layer consisting of type 4M-B'iC, To31° The mulliconcentration of the second P type layer (3) is higher than that of the first P type layer (2) < * 5 x 1o"7a# or more It is preferable that the size is 1-5×10”. (4J (
5) are the first and @2 electrodes formed on the back surface of the substrate (1) and the second Pm layer (37), respectively.

In this example device, the muI concentration of the %1P1P type 2) that forms a Pn junction with the n-type plate (1) is 1 to 5×510”/
-, the crystallinity is very good, and the above P
Desired blue light emission can be obtained near the -n junction. In addition, the second P-type layer (3J has an Aj concentration of 5X10"/-
It is very high and therefore Omitsu (becomes).

Next, a method for manufacturing the above element will be explained.

(13 is a carbon shaken crucible arranged in the reaction tube αυ and placed on the mounting table 14, - is a crucible hanging from the above-mentioned mounting table Q4 so as to surround the crucible I. This is a heat shield plate installed.

The manufacturing method using the praying device will be explained below. .

First, as the first step, 2 to 3
Aj in an amount of 5 ate % was also put into the crucible.

In addition, Ar (argon gas) is used as the atmospheric gas.There is a risk that the quartz reaction tube t1 may be thermally deformed at both temperatures, so the reaction is not shown in the figure. It is preferable to use a cooling means to cool only the trout.

In the next second step, when the 9N type 4L-81CJli plate (1) attached to the tip of the substrate holder lη is immersed in the melt 1e, the melt αG is maintained at a high temperature of 1600 to 1650°C. As a result, the molten liquid causes convection in the crucible 0, and a temperature gradient occurs in the crucible (which forms 1 m).
The first P type layer (2) consisting of M-81C has approximately 10 voices sw/
Epitaxial growth T at a rate of h. *Reject @1p1P
The mulch concentration of type 1) was 1 to S
The sea bream required a thickness of 11 degrees, and was soaked and held for about 1 hour to obtain a thickness of about 10 degrees.

In the final step, Aj is further added to the melt συ while the substrate (1) is kept immersed in the melt ttS to form a second r-type layer (3).

If refused, the second P-type layer (3) should have a concentration of 5 x 10''/- or more, preferably 1 to 5 x 10''/-, as described above.
d or more, and good ohmic characteristics (T is one of the requirements), therefore, in the above Al @ addition device, the pupil was set to be 10 to 15 atm% with respect to 81 in the melt 0. The 2nd P-type layer (formed in such a melt) has a 5118 degree angle of 1 to 2 x 10 degrees/-, and a 2'w1 pole (5) on the surface of the growing layer as shown in Figure 1. In this example, the contact resistance of the electrode was low and the ohmic properties were good.In this example, the first P-type layer (2) and the second P-type layer (3)
Although the 81C blue light-emitting element of the present invention is formed by liquid phase epitaxial growth, it is natural that it may be formed by other growth methods such as vapor phase growth.As is clear from the above explanation, the 81C blue light emitting element of the present invention A type 4N-81C substrate, a first P-type layer deposited on the substrate and containing ^l as a P-type impurity.

The 11th type layer consists of the first P type layer and the Wi2ν type layer containing a large amount of Al, so it is possible to obtain a SIC blue light emitting device with excellent light emitting characteristics and contact resistance with the electrode. .

[Brief explanation of the drawing]

FIG. 1 is a T sectional view showing an example element of the present invention, and FIG. 2 is a f
s1 is a sectional view showing a manufacturing apparatus for manufacturing the element shown in FIG. m”-n type 6 H-81CML (2)-151FW
(6H-'5ic) layer, (3)-second P type (6H81
0) layer. Figure 1 Figure 2

Claims (1)

[Claims] (1) Ni4M-810 substrate, deposited on the ff1j & 6-81 type 6-81
C layer, the first P type 6M-81A layer deposited on the WIIP type 411-1000 layer, and the second P type 6M-81A layer containing a large amount of IAJI.
P type 1. Gic gastric chromogenic luminescent pigment consisting of H-11ONI