Research and development of transistor structure in nano-scale region

In this work, new silicon-on-low-k substrate (SOLK) MOSFET and germanium-on-low-k substrate (GOLK) MISFET are proposed. SOLK-MOSFET with metal back-gate was successfully fabricated using wafer bonding method with low-k material as an adhesive. It was shown that the threshold voltage, the on-current, and the off-current are more effectively controlled by the back-gate bias voltage in SOLK-MOSFETs with metal back-gate than in SOI-MOSFETs with buried back-gate. Ge MISFETs were fabricated with HfO
₂
gate dielectric and W/W
₂
N metal gate which are formed on GOI wafer obtained by a new graded Ge condensation method. Excellent drain current-voltage characteristics and subthreshold characteristics in are obtained in the fabricated GOI-MISFETs.