Epitaxial Growth of Semi-Insulating Gallium Arsenide

Semi-insulating gallium arsenide is grown epitaxially from the vapor phase by using chromyl chloride as a doping agent. The resistivity of the epitaxial layer is greater than 10 8 Ω·cm at room temperature. The temperature dependence of the resistivity gives an activation energy of 0.63 eV. Multilayer structure consisting of semi-insulating layer and n-type layer is obtained without halting growth process by flowing and stopping the chromyl chloride vapor. No dislocation is observed at the boundary between semi-insulating layer and n-type layer, though many dislocations are observed at the epitaxial-substrate interface. It is found that the grown layer becomes semi-insulating only when the donor concentration of the layer is lower than 5×10 15 cm -3 .