Electrical Characteristics of Single, Double and Surround Gate Vertical MOSFETs with Reduced Overlap Capacitance

The vertical MOSFET structure is one of the solutions for reducing the channel length of devices under 50nm. Surround gate structures can be realised which offer improved short channel effects and more channel with per unit silicon area. In this paper, a low technology overlap capacitance, surround gate, vertical MOSFET technology is presented, which uses fillet local oxidation (FILOX) to reduce the overlap capacitance between the gate and the drain on the bottom of the pillar. Electrical characteristics of surround gate n-MOSFETs are presented and compared with results from single gate and double gate devices on the same wafer. The devices show good symmetry between the source on top and source on bottom configuration. The short channel effects of the surround gate MOSFETs are investigate