An improved liquid phase epitaxial growth method for mass production of GaP green LED's

A new liquid phase epitaxial growth system has been developed for mass production of GaP green LED's having a high efficiency. In this system, the n- and p-type layers are grown successively by the different melts on the n-type substrate. GaP substrates are set vertically in a horizontal array in an LPE boat. The main features of this system are that a high external efficiency is attained with an excellent reproducibility, that a large quantity of the substrates can be treated in one run, and that the quality of the growth layers is uniform in one wafer and among the wafers in one run. More than 100 runs have been carried out and the average external efficiency of 0.15 percent is obtained routinely at a current density of 12.5 A/cm
²
for unencapsulated uncontacted mesa diodes and the maximum external efficiency is 0.230 percent at 12.5 A/cm
²
. The high external efficiency may be caused by the high injection efficiency of the hole diffusion current.