The Growth of Epitaxial Gallium Phosphide from the Vapor Phase by Halogen Transport

Gallium phosphide has been grown epitaxially by open tube vapor transport using the system. Although substrates have been used for the majority of the work, the more recent use of Czochralski grown has enabled a reduction in both strain and stacking fault density of the epitaxial layer to be achieved. Sulfur, tellurium, and zinc have been used as dopants in the preparation of both n‐ and p‐type layers, and relationships have been established between the dopant level in the vapor stream and the carrier concentration in the grown crystal. A Schottky diode technique has been used to detect variations in doping level throughout the depth of a slice and, after modifications to the growth process, uniform doping levels have been established. Measurements of the dependence of mobility on carrier concentration over the range 10 14 –10 19 cm −3 have been made on this substantially homogeneous material and consistent results obtained. The levels of compensation in n‐type material have been shown to be between 1 and 2% over the range of carrier concentration . The previously reported dependence of doping level on substrate orientation has been confirmed for (111) surfaces and extended to the (100) and (110) surfaces for homoepitaxy.