论文部分内容阅读
为生长特别适于制备发光二极管用的GaP化合物半导体晶体,发展了一种所谓合成熔质扩散法(SSD)。长成的晶体呈园柱状,由相当大的颗粒组成。生长速率受磷在镓熔液的扩散过程限制。从生长速率可以求得扩散系数,在1100℃是8×10~(-5)cm~2·S~(-1),而激活能是0.65ev。蹄或硫施主杂质从3×10~(17)到4×10~(18)cm~(-3)可重复地掺入,在1150℃的分凝系数分别是0.038和1.0。生长晶体的质量特别好,用改进了的腐蚀液腐蚀晶体几乎看不到碟形坑。仅用单层单次液相外延过程,再通过气相扩散锌就可重复地制出高效率的红色发光结。还研制了一种双层单次外延法,叫作“液相外延生长结”法,并用来制成高效率的绿色LED。用SSD片制备的LED的效率,红光高达7.4％,而绿光高达0.15％。
In order to grow GaP compound semiconductor crystals that are particularly suitable for the preparation of light-emitting diodes, a so-called synthetic melting diffusion (SSD) has been developed. The grown crystals are cylindrical and consist of rather large particles. The growth rate is limited by the diffusion of phosphorus in the gallium melt. The diffusion coefficient can be calculated from the growth rate, which is 8 × 10 -5 cm -2 · S -1 at 1100 ℃, and the activation energy is 0.65ev. The impurities of the hoof or the sulfur donors are repeatedly incorporated from 3 × 10 17 to 4 × 10 18 cm -3 and the segregation coefficients at 1150 ° C. are 0.038 and 1.0, respectively. The quality of the grown crystal is particularly good, with virtually no dishing seen with the improved etching solution. Only single-stage single liquid-phase epitaxy process, and then by diffusion of zinc in the gas phase can be repeatedly produced high-efficiency red light-emitting junction. A two-layer single epitaxial method has also been developed, called the “liquid-phase epitaxial growth junction” method, and is used to make highly efficient green LEDs. The efficiency of LEDs made with SSD films is as high as 7.4% for red and as high as 0.15% for green.