Ron improvement with duplex conduction channel in UHV device

Abstract

This paper presents a low cost innovative duplex channel engineering to simulate and improve specific on-state resistance (Ron) of an Ultra high voltage (UHV) device without compromising on breakdown voltage. In manufacturing of UHV device, tradeoff between on state resistance and breakdown voltage is always present. But with our process design we are able to improve Ron by 15-20% without compromising the breakdown voltage. There are many devices in market with multiple conduction paths, but all these devices use high energy implants. These high energy implants are costly and accuracy of high dose/energy implants is less when compared to low dose/energy implants. Hence we have used a low cost and low energy implants for P-top and N-top to form an extra conduction path. Optimizations are done to obtain high breakdown voltage and lower Ron by varying the P-top and N-top over P-top. As reliability of device is important, we have investigated the interface charge effect on breakdown and the device sustain breakdown voltage for interface charge of 1.5e11. ESD test is also conducted and this structure can pass 4KeV.