RF performance of 28nm PolySiON and HKMG CMOS devices

The impact of scaling in advanced RF/MS-CMOS has been extensively discussed but there has not been a publication that compares the RF characteristics of 28nm high-K metal gate HKMG and PolySiON technologies fabricated in the same facility. In this work, we show that HKMG improves transistor fT and increases varactor tunning range. However, it can actually decrease fmax. We examine how process features made to optimize cost and digital performance impact the RF performance. Process features which improve DC current and gm, including HKMG also give higher fT. However, fmax is sensitive to gate resistance and PolySiON has an advantage here.