A drain extended FinFET with enhanced DC/RF performance for high-voltage RF applications

Abstract

A drain-extended fin field-effect transistor (FinFET) with a dual material gate (DMG) and a high-k field plate (FP), named DF-DeFF, is proposed for high-voltage radio frequency (RF) applications. The FP induces the charge variation in the drain extension, which appears as either the extended depletion in the gate-off state or the electron accumulation in the gate-on state. Along with the FP, the DMG forms a step-like potential variation along the channel, which leads to electron acceleration and the screening effect on the drain-to-source voltage (V DS). These effects give significant advantages to the DC characteristics, including breakdown voltage (V BD) and on-resistance (R on), and the RF characteristics, including transconductance (g m) and output-resistance (r o). Compared to the latest high-voltage RF FinFETs, the DF-DeFF shows a drastic improvement in the major performance indicators such as V BD, cut-off frequency (f T), and maximum oscillation frequency (f MAX). These results indicate that DF-DeFF is a FinFET with sufficient competitiveness even in high voltage circumstances.