Summary: shows a cross-sectional scanning electron microscope (SEM) image.
For PS-STI, no oxide recess is observed at the trench cnmer and a
small bird's beak is formed around the comer.
Fig. 2 SEM image qf PS-STlpmcem
A small birds beak is famed around lhc trench comer
Resolrr and di.scussion: Fig. 3 shows the drain currents for the
conventional STI and the PS-STI processes against gate length in
n-channel and p-channel MOSFETs, respectively. The PS-STI cases
show a large current dow. which is believed to be due to the enlarged
area resulting from the suppression of penctratian in the ma11 bird's
beak into the active area. Fig. 4 shows the reduction of the contact
resistances for the PS-STI compared with the conventional STI
processes. Both N-difksion and P-diffusion contacts show lower
resistances than that of conventional STI.
gale length,mm gatelength. mm
Fig. 3 Dmin currents against n-channel andp-channel gale len,yllt