Title :
Analytical threshold voltage model for ultrathin SOI MOSFETs including short-channel and floating-body effects
Author :
Adan, Alberto O. ; Higashi, Kenichi ; Fukushima, Yasumori
Author_Institution :
Lab. of VLSI Dev., Sharp Corp., Nara, Japan
fDate :
4/1/1999 12:00:00 AM
Abstract :
Short-channel effects (SCE) in ultrathin silicon-on-insulator (SOI) fully depleted (FD) MOSFETs are analyzed and an analytical model for threshold voltage, including the kink effect, is presented. The proposed model accounts for (1) a general nonuniform channel doping profile, (2) the drain-induced Vth- lowering enhancement resulting from the interaction of (a) impact ionization, (b) floating-body, and (c) parasitic-bipolar effects. Good agreement between the proposed model and experimental data is demonstrated. Impact ionization and floating-body effects dominate Vth lowering for drain voltages larger than Vdk≃Bi.λi/3, where Bi is the impact ionization coefficient, and λi is the impact ionization length, a structural parameter which, for a single-drain SOI MOSFET, coincides with the SCE characteristic length λ
Keywords :
MOSFET; doping profiles; impact ionisation; semiconductor device models; silicon-on-insulator; Si; analytical threshold voltage model; drain-induced Vth-lowering enhancement; floating-body effects; general nonuniform channel doping profile; impact ionization length; kink effect; parasitic-bipolar effects; short-channel effects; single-drain transistor; ultrathin SOI MOSFETs; Analytical models; CMOS logic circuits; Doping profiles; Fluctuations; Impact ionization; Leakage current; MOSFET circuits; Semiconductor process modeling; Structural engineering; Threshold voltage;
Journal_Title :
Electron Devices, IEEE Transactions on
