A fully depleted lean-channel transistor (DELTA)-a novel vertical ultra thin SOI MOSFET

A fully depleted lean channel transistor (DELTA) having a gate structure and vertical ultrathin SOI (silicon-on-insulator) structure with selective field oxide is reported. In the deep submicron region, selective oxidation is useful for achieving SOI isolation. It provides a high-quality crystal and a Si-SiO/sub 2/ interface as good as those of conventional bulk single-crystal devices. Using experiments and simulation, it was shown that the gate structure of DELTA has effective channel controllability and its vertical ultrathin (<0.2- mu m) SOI structure provides superior device characteristics, e.g. the reduction of short channel effects, minimized subthreshold swing, and high transconductance. The DELTA layout is consistent with the conventional ULSI circuit layout. Thus, DELTA offers both consistency with conventional MOSFETs and good scalability As a 3-D device. As a result, DELTA provides a promising approach for MOSFET structures of less than 0.1 mu m in size.<>