STUDY ON THE DEVICE CHARACTERISTICS OF A QUASI-SOI POWER MOSFET FABRICATED BY REVERSED SILICON-WAFER DIRECT BONDING

The device characteristics of a quasi-SOI power MOSFET were investigat ed to obtain its optimum device structure. The oxide at the original b ottom surface of the bulk power MOSFET of the quasi-SOI power MOSFET f ormed by reversed silicon wafer direct bonding acts as the buried oxid e of the conventional SOI power MOSFET. The short channel effect of th e quasi-SOI power MOSFET was larger than that in the conventional SOI power MOSFET, It was suppressed by increasing the width of the oxide i n the body region, and the parasitic bipolar effect was suppressed by decreasing it. We also propose a new device structure which can suppre ss the short channel effect and parasitic bipolar effect of a quasi-SO I power MOSFET based on the results of these experiments.