In the present work, preparation of high quality transparent conductive SnO2 thin films by post-oxidation of vacuum evaporated tin, on quartz and silicon substrates is presented. The oxidation was achieved in a short time (90 sec) which is known as rapid thermal oxidation (RTO). Many growth parameters have been considered to specify the optimum conditions, namely, oxidation temperature and oxidation time. Optical, electrical and structural properties of SnO2 films are investigated and analyzed extensively with respect to growth conditions. After obtaining the best results for the preparation of a film. The film was used for the manufacture of MIS devices and for comparison: two types of silicon substrates were used: (n-type and p-type). The optical properties of SnO2 films revealed that the optical band gap is 3.54 eV at optimum condition. The transmission rate of SnO2 films was high (95%) which was reduced with the reduction of oxidation time, while the electrical properties of undoped SnO2 films confirm that these films are n-type and highly conductive. The electrical resistivity was found to be very sensitive to film thickness and substrate temperature.