Linearity and low-noise performance of SOI MOSFETs for RF applications

The MOSFET parameters important for RF application at GHz frequencies: a) transition frequency, b) noise figure, and c) linearity are analyzed and correlated with substrate type. This work demonstrates that, without process changes, high-resistivity silicon-on-insulator (high-ρ SOI) substrates can successfully enhance the RF performance of on-chip inductors and fully depleted (FD)-SOI devices in terms of reducing substrate losses and parasitics. The linearity limitations of the SOI low-breakdown voltage and "kink" effect are addressed by judicious device and circuit design. Criteria for device optimization are derived. A N F = 1.7 dB at 2.5 GHz for a 0.25 μm FD-SOI low-noise amplifier (LNA) on high-ρ SOI substrate obtained the lowest noise figure for applications in the L and S-bands.