Effect of body contacts on high-speed circuits in 90 nm CMOS SOI technology

Silicon-on-insulator (SOI) technology has been successfully used for very high performance VLSI circuits for a few years now. These processes employ partially depleted FET devices with floating bodies. To avoid a time-dependent behavior of these devices in sensitive circuitry, selected bodies can optionally be tied to a controlled potential by means of body contacts. The device then is no longer affected by trapped charges within the channel, thus preventing signal-pattern-dependent variations in V^r. The effect of such body contacts on two representative circuits, a CML buffer and a distributed amplifier, has been studied. It is shown that the introduction of body contacts reduces the bandwidth, increases the jitter but also increases the gain of amplifier circuits.