A large area power MOSFET designed for low conduction losses

A new power MOSFET that is designed to conduct 60 amperes with an on-state resistance of .014 ohms and block 60 volts has been fabricated. The device is used as a low loss synchronous rectifier in an efficient high frequency power supply. Several of the device design criteria include obtaining the largest possible fraction of the ideal blocking voltage and obtaining the minimum on-state resistance. Efficient utilization of the device area requires smaller feature size and shallower junction depths on low voltage power MOSFETs than on high voltage ones. The device reported on is 300 × 300 mils and contains over 60,000 MOSFET cells in parallel. It has a gate length of more than four meters per chip. This device is larger and more complex than any previously reported power MOSFET. It provides an example of how power device processing techniques are approaching those of LSI circuit technology.