The performance measure of GS-DG MOSFET: an impact of metal gate work function

S K Mohapatra, K P Pradhan, P K Sahu and M R Kumar

Abstract

The quantitative assessment of the nanoscale gate stack double gate (GS-DG) MOSFET performance values are numerically calculated with different gate metal work functions (Φ _m = 4.52 eV, 4.6 eV, 4.7 eV). The effect of electrostatic control on dc, analog and RF figures of merit (FOMs) which includes subthreshold slope (SS), drain induced barrier lowering (DIBL), transconductance generation factor (TGF), early voltage (V _EA), intrinsic gain (A_V), cut off frequency (f _T) and transconductance frequency product (TFP), gain frequency product (GFP) and gain transconductance frequency product (GTFP) have been investigated for the model GS-DG MOSFET. Higher TGF and A_V was achieved with Φ _m = 4.6 eV for the device. For a better comparison among the analog/RF FOMs, the threshold voltage (V _th) is maintained at a constant value for different work function cases. To achieve a constant V _th, the channel doping (N_A) and source/drain doping (N_D) is tuned accordingly for all device cases. Superior f _T which is due to higher transconductance (g _m) and lower output conductance (g _d), was observed for the device. In addition, better gain performances i.e. GFP and GTFP were achieved resulting from improved g _m. Thus, the device structure modelled with Φ _m of 4.6 eV can be considered as a better candidate for analog and RF circuit applications