InSb single crystal thin films of less than 0.5-mum thickness sandwiched by Al0.1In0.9Sb layers (with 0.5% lattice mismatch between InSb and Al0.1In0.9Sb ) suitable for magnetic sensors were grown by molecular beam epitaxy on a GaAs(100) substrate and their properties were studied. The large lattice mismatch effect observed at the InSb/GaAs hetero-interface may be almost eliminated. The electron mobility of these InSb thin films was significantly higher than that of InSb thin films directly grown on GaAs substrate. By doping Sn into InSb thin films, almost a one-order smaller value of temperature coefficients for the InSb films were obtained for electron mobility and sheet resistance around room temperature. Thus, by Sn doping, the reduction of temperature dependence was verified for InSb thin films sandwiched by AlInSb layers. As a result, we obtained a high electron mobility and high sheet resistance suitable for magnetic sensors, such as Hall elements and magnetoresistance elements.