Analysis of Transconductance (gm) in Schottky-Barrier MOSFETs

This paper experimentally investigates the unique behavior of transconductance (g(m)) in the Schottky-barrier metal-oxide-semiconductor field-effect transistors (SB-MOSFETs) with various silicide materials. When the Schottky-barrier height (SBH) or a scaling parameter is not properly optimized, a peculiar shape of g(m) is observed. Thus, g(m) can be used as a novel metric that exhibits the transition of the carrier injection mechanisms from a thermionic emission (TE) to thermally assisted tunneling (TU) in the SB-MOSFETs. When the local maximum point of g(m) is observed, it can be expected that an incomplete transition occurs between TE and TU in SB-MOSFETs. When a dopant-segregation (DS) technique is implemented in the SB-MOSFETs, however, the carrier injection efficiency from the source to the channel is significantly improved, although the SBH is not minimized. As a consequence, the peculiar shape of the g(m) disappears, i.e., a complete transition from TE to TU can be enabled by the DS technique.