0.35-μm asymmetric and symmetric LDD device comparison using a reliability/speed/power methodology

The reliability and performance of NMOSFET asymmetric LDD devices (with no LDD on the source side) are compared with that of conventional LDD devices. The results show that asymmetric LDD devices exhibit higher I/sub dsat/ and larger I/sub sub/ TO maintain the same hot-carrier lifetime, asymmetric LDD devices must operate at lower V/sub dd/. For the same hot-carrier lifetime, we show that ring oscillators with asymmetric LDD devices can achieve 5% (10% if PMOSFET also had asymmetric LDD) higher speed and 10% lower power.