Doping of InSb thin films with elements of groups II and VI

Abstract

The processes of incorporation of tellurium, selenium, sulphur, cadmium and zinc into flash-evaporated InSb thin films are investigated. The dopings are performed by the co-evaporation of the dopant materials and InSb from separate sources. Their effects are investigated using Hall effect measurements carried out at 77K both on the as-evaporated films and on the same films subjected to regrowth from the melt. The electrical properties of regrown films are close to those of bulk InSb with the same donor or acceptor concentration. The electrical and structural properties of as-evaporated films doped with tellurium, selenium and sulphur are consistently explained on the assumption that, on doping, thin layers of In2Te3, In2Se3 and In2S3 respectively are formed on the film grains. At a substrate temperature Ts of 700K the sticking coefficients of tellurium, selenium and sulphur are close to unity and those of cadmium and zinc are several orders of magnitude lower. The main features of the process of incorporation of the dopants can be qualitatively explained within a thermodynamic framework describing the chemical equilibrium. © 1986.