Improved low temperature characteristics of p-channel MOSFETs with Si _1-xGe _x raised source and drain

Abstract

P-channel metal-oxide semiconductor field-effect transistors with Si 1-xGe x raised source and drain (RSD) have been fabricated and further studied for low temperature applications. The Si 1-xGe x RSD layer was selectively grown by ANELVA SRE-612 ultra-high vacuum chemical vapor deposition (UHVCVD) system. Compared to devices with conventional Si RSD, improved transconductance and specific contact resistance were obtained, and these improvements become even more dramatic with reducing channel length. Well-behaved short channel characteristics with reduced drain-induced barrier lowering (DIBL) and off-state leakage current are demonstrated on devices with 100 nm Si 1-xGe x RSD, due to the resultant shallow junction and less implantation damage. Moreover, temperature measurements reveal that Si 1-xGe x RSD devices show more dramatic improvement in device performance at low temperature (-50°C) operation, which can be ascribed to the higher temperature sensitivity of the Si 1-xGe x sheet resistance.