Quantum Effect in Sub-0.1 µm MOSFET with Pocket Technologies and Its Relevance for the On-Current Condition

The effect of the inversion layer quantization for metal-oxide-semiconductor field-effect transistors (MOSFETs) under off-current as well as on-current condition is investigated by simulation. The main focus is given for MOSFETs with an optimized pocket profile. It is shown that the optimized pocket profile for gate length down to 70 nm MOSFET causes an enhancement of the threshold voltage increase with reducing gate length. This is due to the effective impurity-concentration increase caused by the pocket implantation, while the quantum effect itself is weakened by the short-channel effect. Though the quantum effect weakens from source to drain due to the short-channel effect under on-current condition, its strength at source determines the whole MOSFET performance for the gate length down to 70 nm. This was confirmed by Monte Carlo simulation including the quantum effect by an effective potential method.