Novel power VDMOSFET structure with vertical floating islands and trench gate

Abstract

301-307A novel power VDMOSFET (vertical double-diffused MOSFET) structure, simulated using PISCES-II, a 2-dimensional numerical device simulator has been described. The proposed device structure is based on the floating islands (FLI)-diode concept and trench gate technology. Extensive simulations were performed to understand physics of the device through various internal electrical quantities like potential distribution, electric field, etc. in different regions of the device both in on/off states.The simulation results show that the new device has a low on-resistance by virtue of reduced electric field in its drift region as well as due to the removal of parasitic JFET region resistance. Trench gate acts as a field plate to avoid the punch-through thus enhancing the breakdown voltage. For a 100 Volts design, an approximate 15% increase in the breakdown voltage has been observed in the proposed device compared to the conventional FLIMOSFET without trench gate