An Accumulation Mode RF Laterally Double Diffused MOSFET With Improved Performance

In this letter, an improved radio frequency (RF) laterally double diffused metal-oxide-semiconductor (LDMOS) transistor with the application of accumulation mode stripe (AMS) is proposed and fabricated in a 0.35-μm CMOS process without extra process steps or masks. AMS accumulates electrons at the surface of the drift region, which result in an improvement in the saturated drain current. Moreover, AMS modulates the electric field distribution across the drain extension region by inducing an electric field peak at its edge. Power performances at 3.1 GHz for the AMS-LDMOS show a 0.75-W/mm continuous-wave output power density with 21-dB linear gain and over 52% drain efficiency at a supply voltage of 32 V. In comparison with conventional RF LDMOS with source field plate, the proposed device exhibits 1-1.5 dB higher linear gain along with improved linearity.