InSb thin films were grown on GaAs (1 0 0) substrates by molecular beam epitaxy (MBE). N-type impurity (Sn and Si) doping Of InSb was investigated for the purpose of reducing its temperature dependence of resistivity. It was found that stable Sn-doped InSb thin films with large electron mobility (4.5 x 10(4) cm(2)/Vs) and sheet electron concentration (7.2 x 10(12) cm(-2)) can be fabricated. Magneto-resistance (MR) devices using these films show a large enough MR effect and an extremely small temperature dependence of resistance.