Complementary SOI MESFETs at the 45-nm CMOS Node

Silicon-on-insulator (SOI) metal-semiconductor field-effect transistors (MESFETs) with complementary n- and p-type channels have been fabricated using a commercial 45-nm CMOS process. The current drive and transconductance of the n-MESFET is approximately three times larger than that of the p-MESFET due to the higher electron mobility. Both devices operate in depletion mode with the threshold voltage of the n-MESFET being approximately -0.4 V, while that of the p-MESFET is ~0.3 V. The MESFETs have multiple gigahertz cutoff frequencies and can withstand drain bias in excess of 4 V making them attractive for analog- and mixed-signal applications that require higher operating voltages than the baseline CMOS. The p-MESFET has higher leakage current due to the lower Schottky barrier height to the p-type channel.