Floating Island and Thick Bottom Oxide Trench Gate MOSFET (FITMOS) -60V Ultra Low ON-Resistance Novel MOSFET with Superior Internal Body Diode-

Abstract

A MOSFET structure named FITMOS has been successfully developed and exhibits record-low loss in the 60 volt breakdown voltage range. The device has a body diode with superior reverse recovery characteristics and exhibits an extremely small value for RonQgd. The distinctive feature of this device is the use of floating islands formed by self-alignment and trench gates with a thick oxide layer on the bottom. This structure can also be used for the terminal portion of the device, so the increase in the number of fabrication process steps is less than 5%. Moreover, the rate of non-defective-gates in 3-by-4-mm rectangular devices on an 8-inch wafer is at least 98%.