Transport properties of Sn-doped InSb thin films and applications to Hall element

The temperature dependence of the transport properties of undoped and Sn-doped InSb single crystal thin films grown on GaAs substrates by MBE were investigated. The temperature dependence of undoped InSb thin films was large and had maximum near room temperature, whereas the Sn-doped thin films showed very small and monotonic decrease with increasing temperature. The electron mobility of the films varied significantly in the growth direction from the InSb/GaAs hetero-interface to the InSb thin film surface. This large variation of the electron mobility in the growth direction explained the observed temperature dependence of the electron mobility for these films. The large variation of the electron mobility in the growth direction was described by a simple model of two layers with a low electron mobility layer near the hetero-interface and the other with a high electron mobility. These InSb films were used to fabricate practical and highly sensitive Hall sensors with a very small temperature dependence.