Characterization and Modeling of 28nm RF MOSFETs and SiGe HBTs

Abstract

Both the second and third order intermodulation linearities (IP3 and IP2) are characterized on 28nm RF MOSFETs. The impacts of biasing, device size, frequency, and gate length on IP3 are discussed. With both DC and RF tuning, the PSP core model based design kit provides reasonable fitting result, enabling comparison of IP3 simulation with measurement. Effective gate voltage IP3, a figure-of-merit for IP3 extracted from RF IP3 measurement is proposed to include important output conductance related nonlinearities and compared with traditional gate voltage IP3. The real part of Y22 is generally fitted by adjusting body resistance, which is found to be insufficient experimentally. A new tradeoff between imaginary part of Y22 and real part of Y22 fitting is identified and used to enable fitting of both real and imaginary part of Y22 across a wide range of frequency and bias. For 200 GHz HBTs, a simplified model is used to analyze characterization result of IP2. The impacts of biasing, device size, frequency and breakdown version on IP2 are discussed.