0.5 µm Silicon-on-Sapphire Metal Oxide Semiconductor Field Effect Transistor for RF Power Amplifier Applications

Abstract

0.5 µm thin-film silicon-on-sapphire (SOS) metal oxide semiconductor field effect transistors (MOSFETs) are investigated for applications in RF power amplifiers. Detailed static and pulsed I–V characteristics are measured to distinguish between fully depleted and partially depleted SOS MOSFETs. We have performed the first detailed large-signal load-pull characterization of SOS MOSFETs at 2 GHz with a Maury load-pull system with automated tuners. The maximum output power (Pout) of 18 dBm, maximum gain (G) of 12.5 dB and maximum power-added efficiency (PAE) of 55% were achieved. Third-order intermodulation (IM3) and adjacent channel power ratio (ACPR) were measured to characterize the linearity of an SOS MOSFET power amplifier. For the optimum design of RF power amplifiers, impedance matching information is essential as revealed by the large-signal load-pull measurements.