Evaluation of the partially-depleted silicon-on-sapphire technology for microwave amplifiers and other prospective applications

The gigahertz microwave performances of simple floating-body MOSFET on a 0.5-μm partially-depleted (PD) silicon-on-sapphire (SOS) CMOS technology is reported. The microwave small-signal gain increases with V_DS despite the DC kink resulted from the floating body of the PD-SOS MOSFET. However, minimum value of F_min is obtained with low V_DS in saturation region. In large-signal amplification, a class B operation of the PD-SOS nMOSFET gives an almost 40% peak power-added efficiency (PAE) and a maximum output power of more than 32 mW/mm using 3 V power supply regardless of the apparent lower drain-source breakdown voltage (BV_DS). Based on the measurement results, the PD-SOS technology is evaluated for implementations of microwave amplifiers: low-noise amplifier and power amplifier. The underlying device physics and. brief circuit design guidelines are given. Prospective applications of SOS CMOS technology in microwave photonics are also discussed.