This paper describes the Shallow Trench Isolation (STI) stress effect on 45 degree rotated MOSFET layouts. 45 degree rotated PMOS layout with large Sa (active space) shows 15% increase in saturation drain current (Idsat)as compared to the non-rotated ones. On the other hand, PMOS layout with minimum Sa and same rotation show 3.8% Idsatenhancement only. This is because when rotated 45 degree, the channel orientation changes from <110> to <100> axis. This enhances the PMOS Idsatwith large Sa. At minimum Sa, the Idsatenhancement is small because the PMOS is at high STI stress. For <110> or non-rotated layouts, the STI stress is observed to increase the Idsatby 14 %. The impact of STI stress effect on PMOS with minimum Sa is negligible at <100> or rotated. For NMOS, no Idsat enhancement or degradation is observed on 45 degree rotated layouts. Finally, we have studied the effect of using 45 degree rotated PMOS in ring oscillator circuit.
