Reliable Spin‐On Source for Acceptor Diffusion into III/V Compound Semiconductors

Abstract

A long‐term reliable spin‐on source for open tube p+‐diffusion into III/V compound semiconductors has been developed. This source consists of a water/alcoholic solution of zircon alcoholate doped with zinc chloride. After spinning and drying in air ambient at 300°C a glassy film of on the semiconductor surface acts as solid‐state source for the subsequent diffusion. Unlike state‐of‐the‐art silica‐based sources, this solution exhibits an excellent long‐term durability. Furthermore, the thermal expansion coefficient of zirconia is well matched to that of most III/V compound semiconductors and yields very stable films even at high temperatures to permit essentially stress‐free diffusion. Diffusion experiments into have been carried out in the temperature range between 600° and 700°C. The hole concentrations and diffusion coefficients obtained with this source are rather close to those obtained by other diffusion techniques. The simple handling and long‐term durability of the zirconia‐based solutions, however, represent essential advantages over other p+‐diffusion techniques used in the technology of III/V compound semiconductors.