Metal-oxide semiconductor transistors fabricated on Si/Al2O3/Si structures

Metal-oxide semiconductor field effect transistors (MOSFETs) were fabricated by polycrystalline-Si gate process on double heteroepitaxially grown Si(100)/Al2O3(100)/Si(100) structures in order to characterize the Si on insulator (SOI) structures. To realize the SOI structures, at first, the epitaxial Al2O3(100) film was grown on a 2-in. Si(100) wafer, and then, Si epitaxial film was grown on the Al2O3/Si by the chemical vapor deposition method. The SOI wafers were able to be handled in the same way as Si wafers during the device fabrication process. From ID-VD and ID-VG properties of the MOSFET, the transistor action was confirmed, and the threshold voltage of 0.4 V and the effective mobility of 540 cm2/V s at VG − VT = 4.0 V were obtained. The epitaxial Si layer was p-type, and the impurity concentration was considered to be 5×1015 cm−3. These results were very similar to those obtained from Si on sapphire epitaxial films.