Electrical Properties of n-Type Epitaxial Films of Silicon on Sapphire Formed by Vacuum Evaporation

Abstract

n‐type epitaxial films of silicon on sapphire were successfully obtained with a high degree of reproducibility by adding antimony during the evaporation of undoped silicon having the resistivity of 2400 Ω·cm. An attempt to control resistivities of films was made by changing the temperatures of the antimony source. The dependence of the Hall mobilities and the carrier concentrations of the films upon temperatures was measured at temperatures ranging from 77°K to room temperature. The Hall mobility of films grown on (0001) sapphire at a substrate temperature of 900°C was higher than that of films with a similar resistivity grown on$\text{(1̄012)}$ sapphire. Effects of the thermal oxidation and the subsequent annealing of these as‐grown films upon their electrical properties were investigated. After these treatments a remarkable rise in the Hall mobilities of the films was observed at temperatures ranging from 77°K to room temperature.