Substrate Majority Carrier-Induced NLDMOSFET Failure and Its Prevention in Advanced Smart Power IC Technologies

This paper discusses substrate majority carrier conduction and prevention for an n-type lateral double diffused MOSFET (NLDMOSFET) device in Smart Power IC technologies. Substrate majority carrier current poses severe electrical and thermal stress for NLDMOSFET devices and causes many system integration issues for advanced Smart Power IC technologies. A single- and multi-iso isolated NLDMOSFET is proposed and experimentally verified to eliminate the problem. Tradeoff between device size, safe operating area (SOA), substrate current, and NLDMOSFET-device power dissipation has been studied. Detailed analysis of device SOA for conventional and isolated devices and techniques to improve the device SOA has also been provided