Improvement of direct-tunneling gate leakage current in ultra-thin gate oxide CMOS with TiN gate electrode using non-doped selective epitaxial Si channel technique

A non-doped selective epitaxial Si channel technique has been applied to ultra-thin gate oxide CMOS transistors with TiN and polysilicon gate electrodes, and its effect on direct-tunneling gate leakage current has been investigated. It was found that the epitaxial Si channel noticeably reduces the direct-tunneling gate leakage current in both the TiN and polysilicon gate electrode cases. Improved drain current drive and transconductance of the epitaxial channel MOSFETs with ultra-thin gate oxides in the direct-tunneling regime has been also demonstrated.