Novel Step Field Plate RF LDMOS Transistor for Improved BVDS-Ron Tradeoff and RF Performance

In this article, a novel step field plate (SFP) laterally diffused metal–oxide–semiconductor (LDMOS) structure is proposed for improved breakdown voltage- ON resistance tradeoff and better RF performance. The proposed structure could be easily integrated into the CMOS process flow using four additional noncritical masks. The known materials like fully silicided polysilicon and silicon nitride (SiN) are used as FP and dielectric, respectively. The proposed design improves the device performance by uniformly distributing the electric field in the drift region. The higher drift doping for the same OFF-state breakdown voltage improves the ON resistance by
$\sim 2.5\times $
and ON-state breakdown voltage by
$\sim 2\times $
. Significant improvements in frequency behavior and flat power response are also observed. The device physics behind different observations are explained using detailed TCAD simulations.