Title :
A physical charge-based model for non-fully depleted SOI MOSFET´s and its use in assessing floating-body effects in SOI CMOS circuits
Author :
Suh, Dongwook ; Fossum, Jerry G.
Author_Institution :
Dept. of Electr. Eng., Florida Univ., Gainesville, FL, USA
fDate :
4/1/1995 12:00:00 AM
Abstract :
A new model for the non-fully depleted (NFD) SOI MOSFET is developed and used to study floating-body effects in SOI CMOS circuits. The charge-based model is physical, yet compact and thus suitable for device/circuit simulation. Verified by numerical device simulations and test-device measurements, and implemented in (SOI)SPICE, it reliably predicts floating-body effects resulting from free-carrier charging in the NFD/SOI MOSFET, including the purportedly beneficial supra-ideal sub-threshold slope due to impact ionization and a saturation current enhancement due to thermal generation. SOISPICE CMOS circuit simulations reveal that the former effect is not beneficial and could be detrimental, but the latter effect can be beneficial, especially in low-voltage applications, when accompanied by a dynamic floating-body effect that effectively reduces static power. The dynamic floating-body effects are hysteretic, however, and hence exploitation of the beneficial ones will necessitate device/circuit design scrutiny aided by physical models such as the one presented herein
Keywords :
MOSFET; SPICE; impact ionisation; semiconductor device models; silicon-on-insulator; SOI CMOS circuits; floating-body effects; free-carrier charging; impact ionization; low-voltage applications; nonfully depleted SOI MOSFETs; numerical device simulations; physical charge-based model; saturation current enhancement; static power; supra-ideal sub-threshold slope; Circuit simulation; Circuit synthesis; Circuit testing; Current measurement; Hysteresis; Impact ionization; MOSFET circuits; Numerical simulation; Predictive models; Semiconductor device modeling;
Journal_Title :
Electron Devices, IEEE Transactions on