Ensemble Monte Carlo study of channel quantization in a 25-nm n-MOSFET

We develop a self-consistent, ensemble Monte carlo device simulator that is capable of modeling channel carrier quantization and poly silicon gate dep letion in nanometer-scale n-MOSFETs, A key feature is a unique bandstructur e expression for quantized electrons, carrier quantization and polysilicon depletion are examined against experimental capacitance-voltage (C-V) data. Calculated drain current values are also compared with measured current-vo ltage data for an n-MOSFET with an effective channel length (L-eff) of 90 n m. Finally, the full capabilities of the Monte Carte simulator are used to investigate the effects of carrier confinement in a L-eff = 25 nm n-MOSFET. In particular, the mechanisms affecting the subband populations of quantiz ed electrons in the highly nonuniform channel region are investigated. Simu lation results indicate that the occupation levels in the subbands are a st rong function of the internal electric field configurations and two-dimensi onal (2-D) carrier scattering.