Investigation of the zinc diffusion process into epitaxial layers of indium phosphide and indium-gallium arsenide grown by molecular beam epitaxy

Abstract

The results of an investigation of the peculiarities of the zinc diffusion process into epitaxial layers of indium phosphide and indium-gallium arsenide aimed at the fabrication of an avalanche photodiode for a single-photon detector are presented. The diffusion of zinc into indium phosphide through an intermediate layer of indium-gallium arsenide ensures better surface quality compared with the direct diffusion of zinc into the indium phosphide layer. We discovered that systems such as a quartz reactor with resistive heating with an internal solid-state source of zinc vapor and the reactor of a metal-organic chemical vapor deposition setup with hydrogen as a carrier gas make it possible to achieve similar concentrations of doping p-type impurity, which exceed 2×1018cm−3. The depth of zinc diffusion in the indium phosphide layer ranged from 2 to 3.5 µm, depending on the temperature and duration of the diffusion process. Such depths are required for fabrication of effective avalanche photodiodes.