Diffusion of Beryllium into Gallium Phosphide

Abstract

The acceptor Be has been diffused into GaP from a liquid Ga–Be–P diffusion source at temperatures ranging from 600 to 1000°C. The diffusion behavior was found to be a function of the growth origin of the substrates, and the depth of the diffused junctions was not proportional to the square root of the diffusion time over part of the temperature range investigated. Diffusion profiles were obtained in liquid encapsulated Czochralski material at 1000, 900, and 800°C by the atomic absorption technique, and the 1000 and 900°C profiles were analyzed by the Matano method. In the high‐concentration range investigated it is found that the diffusion coefficient varies nonmonotonically with concentration and reaches a maximum value of 8.5×10⁻⁸ cm²/sec at a concentration of 2.5×10¹⁹ cm⁻³ at 1000°C. Comparison with Zn diffusion shows that the diffusion coefficient of Be is approximately one order of magnitude larger than that of Zn at 100°C and that a strong similarity exists in the concentration dependence of the diffusion coefficient of these two impurities.