Wide tuning-range MOS varactors based on SOI

MOS varactors based on SOI substrate with very wide tuning-range are presented in this paper. Compared with bulk silicon substrate, varactors based on SOI substrate have wider tuning-range due to less parasitic capacitance. These varactors including n-type accumulation mode MOS varactor (AMOS), n-type gated diode (GD) and p-type GD. are fabricated with the same CMOS process technology and compared with bulk ones. Results show SOI varactors' tuning range is wider than bulk ones to a large extent.