Study of TiO2 and SiO2/TiO2 as Gate Dielectric Maaterials

MOS capacitors with TiO2 and TiO2/SiO2 dielectric layer were fabricated and characterized. TiO2 films where physical characterized by Rutherford Backscattering, Fourier Transform Infrared Spectroscopy and Elipsometry measurements. Capacitance-voltage (1MHz) and current-voltage measurements were utilized to obtain, the effective dielectric constant, effective oxide thickness (EOT), leakage current density and interface quality. The results show that the obtained TiO2 films present a dielectric constant of approximately 40, a good interface quality with silicon and a leakage current density, of 70 mA/cm2 for VG = 1V, acceptable for high performance logic circuits and low power circuits fabrication, indicating that this material is a viable substitute for current dielectric layers in order to prevent tunneling currents. The results for SiO2 (6nm) /TiO2(58nm) layer show a reduction of 3 orders of magnitude in leakage current density and an effec tive dielectric constant of 20, also viable to substitute the usual dielectric material in CMOS fabrication.