Improvement of P-channel SOI LDMOS transistor by adapting a new tapered oxide technique

On-resistance of P-channel REduced SURface Field (RESURF) lateral double-diffused MOS (LDMOS) transistors has been improved by using a new tapered TEOS field oxide on the drift region of the devices. The new tapered oxidation technique provides better uniformity, less than 3%, and reproducibility. With the similar breakdown voltage (V/sub B/), at V/sub gs/=-5.0 V, the specific on-resistance (R/sub sp/) of the LDMOS with the tapered field oxide is about 31.5 m/spl Omega//spl middot/cm/sup 2/, while that of the LDMOS with the conventional field oxide is about R/sub sp/=57 m/spl Omega//spl middot/cm/sup 2/. The uniformities of R/sub sp/ and V/sub B/ are less than 5 and 3%, respectively.