A new low specific on-resistance Hk-LDMOS with N-poly diode

摘要

A new structure of the laterally diffused metal-oxide-semiconductor transistors (LDMOS) using a high permittivity (Hk) dielectric is proposed, and its mechanism is investigated by 2-D TCAD simulation. The breakdown voltage (BV) is remarkably increased by using the Hk dielectric. Moreover, a reverse biased poly diode is first introduced on the Hk dielectric, which assists the n-drift region forming an electron accumulation layer to reduce the specific on-resistance (R_(on,sp)) further. Compared with a conventional LDMOS with the same geometry, the BV increases by 24%, and the R_(on,sp) decreases approximately by 50%. Besides, the proposed structure is less sensitive to the n-drift region doping deviation, and exhibits a larger safe operating area (SOA).