Threshold voltage study of scaled self-aligned In0.53Ga0.47As metal oxide semiconductor field effect transistor for different source/drain doping concentrations

A multi-gate n-type In_0.53Ga_0.47As metal oxide semiconductor field effect transistor is fabricated using the gate first self-aligned method and air-bridge technology with an 8 nm thick Al₂O₃ oxide layer. By scaling the gate length down to 200 nm, the effect of two different source/drain doping concentrations on device parameters such as threshold voltage, I_on/I_off ratio and subthreshold swing were investigated at room temperature. Increasing the value of the source/drain doping concentration revealed an enhancement in all investigated parameters. Sheet resistance and contact resistance values were improved as well. The negative shift in threshold voltage for shorter gate lengths was observed for both source/drain concentrations; however, the shift in threshold voltage was less (~0.4 V) for the higher source/drain doping concentration.