Quasi-Planar Tri-gate (QPT) bulk CMOS technology for single-port SRAM application

Abstract

Quasi-Planar Tri-gate (QPT) Bulk MOSFETs are fabricated simply by slightly recessing the shallow trench isolation (STI) oxide prior to gate-stack formation. In this cost-effective manner, 7% higher performance with lower leakage current in QPT bulk devices (vs. planar bulk devices) is achieved. QPT-based single-port SRAM characteristics can be improved by employing circuit design techniques (i.e., read- and write-assist circuitry) to compensate for unequal improvements in n-channel vs. p-channel QPT devices, to improve cell yield.