Applications of surface analysis to Oxide Thin Film Devices

Surface analysis has been applied to obtain electronic properties for ultrathin high-k dielectric gate oxide thin films, metal gate stack in CMOS, and transparent conductive oxide thin film transistors (TFTs) incorporating an oxide active channel layer. The band alignment in HfZr silicate gate dielectric thin films showed that the band gap, the valence band offset and the conduction band offset increased as the SiO2 content increased, which yielded a substantially reduced gate leakage current density. TheTiN/(LaO or ZrO)/SiO2 metal gate stack structures in CMOS demonstrated that a flat band voltage (VFB) shift could be controlled in TiN/(LaO or ZrO)/SiO2 gate stack structures. The electrical characteristics of GIZO TFTs mainly depend on the contents of indium (In) and gallium (Ga). The band gap energies of the GIZO thin films increased with the increase in their Gallium (Ga)/Indium (In) ratios. The barrier height of GIZO/Mo also increased by increasing in the Ga/In ratio, and then the threshold voltages positively shift. We also applied AES and REELS analyses to confirm the origin of intrinsic photoluminescence emission from subdomain graphene quantum dots