The Dependence of the Performance of Strained NMOSFETs on Channel Width

The dependence of the performance of strained NMOSFETs on channel width was investigated. When the channel width was varied, the stress in the channel varied accordingly. This changed the electron effective mass and, consequently, the on-state current I _on. By shrinking the channel width of a strained NMOSFET from 1 to 0.1 mum and by keeping the channel length at 55 nm, the on-state drain current per unit channel width was enhanced by 22%. The gate leakage current was also affected by the stress in the channel, which can be explained by the increase in hole barrier height at the Si/SiO₂ interface. Furthermore, when the film stress was increased by 1 GPa, the gate leakage current density Jg of a strained NMOSFET with a channel width of 0.1 mum and a length of 55 nm under a negative bias -3 V was reduced by 63%.