JPS5980981A - Gallium phosphorus green color emitting diode and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve the light emitting efficiency of the titled diode by a method wherein the first n-layer with the impurity concentration almost similar to that of a substrate, the second n-layer with the impurity concentration lower than that of the first layer by one figure or more and less thickness and a p-layer formed on the second layer are provided on a substrate. CONSTITUTION:An n type gallium phosphorus substrate 1 with impurity concentration of 1-3X10<17>cm<-3> is contained in a carbon boat together with melt in hydrogen atmosphere at high temperature (11). At this time, after mixing hydrogen sulfide within the hydrogen atmosphere for about one minute and introducing sulfur to be the main donor impurity into the melt the melt is cooled down to epitaxially grow the first n- layer 12. At this time, the impurity concentration of the first n-layer 2 30-50mum thick is almost similar to that of substrate 1 i.e. 1-5X10<17>cm<-3>. Then the melt is left for a long time (13). Finally the atmosphere converted from hydrogen to argon is cooled down after nitrogen is dissipated to epitaxially grow the second n-layer 14. The second n-layer 4 with the impurity concentration of 0.5-5X10<16>cm<-3> is 10-20mum thick. Then zinc vapor is successively introduced to liquid epitaxially grow a layer with impurity concentration of 5-10X10<18>cm<-5>.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gallium phosphorus green light-emitting diode that contains almost no nitrogen and silicon and emits high-intensity short-wavelength green light, and a method for manufacturing the same.

Conventionally, using gallium phosphorus (GaP), the emission wavelength was 555j.
It has been said that for a light emitting diode that emits pure green light of nm wavelength, it is necessary not to mix nitrogen near the Pn junction and to reduce the density of the N layer. For example, the special public official court Sho 57-111
In the 1984 publication, the first Ii!
As shown in J(a) and (b), the impurity concentration was 1016♂ after two times of n-layer growth @(2), the substrate side was rich in nitrogen (the bonding side was n1l containing no nitrogen).
(to) is formed.

However, in the inventor's research, the number of Pn junctions +
The presence of nitrogen in the vicinity of μm tends to cause absorption of wavelength light, and if a low impurity layer is grown immediately from the substrate, the crystallinity deteriorates at the interface, and currents and heat generation phenomena that do not contribute to light emission are likely to occur. Although silicon is used as the main donor impurity in the above literature, it was concluded that silicon in gallium phosphorus is undesirable because it is difficult to handle and a small amount of silicon destroys the crystallinity of the light emitting layer and shortens its life.

The present invention has been made in consideration of the above points, and relates to a gallium phosphorus green light emitting diode that stably emits short wavelength light with high luminous efficiency, and a method for manufacturing the same. This will be explained in detail based on the following.

FIG. 2 shows the T! FIG. 3 is an impurity concentration diagram of a gallium phosphorous green light emitting diode manufactured in this way.

First, using a carbon boat, 1 to 5W, 10+7 countries-
n-type gallium phosphide substrate Il+ with impurity V/1m degree of 5
XtU is held at high temperature in a hydrogen atmosphere together with the melt. At this time, hydrogen sulfide is mixed in the hydrogen atmosphere for about 1 minute to introduce sulfur, which becomes the main donor impurity, into the melt, and then the temperature is lowered and the first - The L pita cow grows d2゜The first nM1121 formed at this time is 1 to 5 x 10''
a+-', the impurity temperature is about the same as that of the substrate +11, and the thickness is 60 to 50 μm. After that, hold J31 for a long time, or in the previous turn, the sulfur introduced in the above step will scatter, and in the second half, in J & cut, the ammonia gas will be completely 0.
．． 1 to 0.4 Sill N
As a result, the sulfur and silicon concentrations of the M fruit melt decrease. Preferably the silicon is lPPm1.
] It is preferable to precipitate the nitride so that it becomes . Finally, the atmosphere is switched from hydrogen to argon to prevent silicon from being mixed in from the reaction mixture, and the temperature is lowered while avoiding the scattering of nitrogen introduced from ammonia gas, and the second n-layer is epitaxially grown. The second n ffl +41 thus formed is 0.5 to 5×10
The thickness in cm is 10 to 2 L) Pm. Then, zinc vapor is introduced and the thickness is 5 to 10 x 10" Pm.
u51 to grow the P layer (5) of ' by liquid phase epitaxial growth
As described above, the present invention is characterized in that the first nl- of impurity #
The impurity concentration of f is formed on the first n layer 60.
Since this is a gallium phosphorous green light-emitting diode with a second n-layer that is one order of magnitude lower and thinner, and a p-layer formed on the second n-layer, the crystallinity of each layer is not disturbed. (The 0 layer near the Pn junction can be lowered by 1 degree, resulting in high luminous efficiency, and since there is almost no nitrogen in the atmosphere, pure green light is emitted.Specifically, Barako emits light after chip coating. With an efficiency of 0.12%, an average brightness of 115 mcd, and an emission wavelength of 555 nm, it is about 1 times faster than conventional products even in high-temperature and high-humidity life tests.
There was no low brightness for a long period of time.

In addition, as mentioned above, a 1L light emitting diode was grown by liquid phase epitaxial growth of an n layer on an n-type phosphorus substrate, and then a nitride of sl in the melt was precipitated, and then in an argon atmosphere. Since the second nt@ is grown by liquid phase epitaxial growth and then pH is formed, the valleys of the N44 layer C, especially silicon, near the P-rejunction are removed, making it easy to produce.

2. EA is a temperature process diagram of liquid phase epitaxial growth of a gallium phosphorous green light emitting diode according to an embodiment of the present invention, and FIG. 3 is an impurity concentration diagram of a gallium phosphorous green light emitting diode according to an embodiment of the present invention.

11th board, +2th IJ 1 n layer, (4F-jB
2 n-layer, 15)...Pm.

Claims (1)

[Claims] ill The first n layer formed on the n-type gallium phosphorus substrate has an impurity concentration substantially equal to that of the substrate, and the impurity concentration formed on the WSl n layer is higher than that of the first n layer. The second n- layer is more than an order of magnitude lower and the thickness is thinner, and the second n- layer is formed on the second n layer.
A gallium phosphorus green light emitting diode characterized by comprising a layer. (2) After growing a first n-layer in liquid phase epitaxially on an n-type gallium phosphorus substrate, depositing 11'91 of Sl nitride in the melt, and then growing a second n-layer in an argon atmosphere. n1
Plii is grown by liquid phase epitaxial growth, and then Plii is grown by liquid phase epitaxial growth.
A method for manufacturing a gallium phosphorus green light emitting diode, characterized in that it forms a gallium phosphorus green light emitting diode.