Effects of back gate bias on radio-frequency performance in partially depleted silicon-on-inslator nMOSFETs

Abstract

The effects of back gate bias (BGEs) on radio-frequency (RF) performances in PD SOI nMOSFETs are presented in this paper. Floating body (FB) device, T-gate body-contact (TB) device, and tunnel diode body-contact (TDBC) device, of which the supply voltages are all 1.2 V, are compared under different back gate biases by different figures of merit, such as cut-off frequency (fT), maximum frequency of oscillation (fmax), etc. Because of the lack of a back gate conducting channel, the drain conductance (gd) of TDBC transistor shows a smaller degradation than those of the others, and the trans-conductance (gm) of TDBC is almost independent of back gate bias. The values of fT of TDBC are also kept nearly constant under different back gate biases. However, RF performances of FB and TB each show a significant degradation when the back gate bias is larger than ∼20 V. The results indicate that TDBC structures could effectively improve the back gate bias in RF performance.

Effect of cryogenic temperature characteristics on 0.18-μm silicon-on-insulator devices

“…The SOI MOS offers several benefits over bulk MOS technology, such as latch-up immunity, especially in the space application due to its excellent radiation hardness. [5][6][7] The long-recognized advantages of MOS working at cryogenic temperature have encouraged investigators in many fields all over the world since the 1970s. [8] The main advantages of MOS under cryogenic temperature are associated with an increased carrier mobility, better turn-on capabilities, higher saturation velocity, higher thermal and electrical conductivity, lower power consumption, reduced thermal noise, and decrease of junction leakage currents.…”

Ultra-low temperature radio-frequency performance of partially depleted silicon-on-insulator n-type metal–oxide–semiconductor field-effect transistors with tunnel diode body contact structures

“…[5] In contrast from the conventional body contact structure, TDBC structure efficiently suppresses FBE and body-instability problems with smaller areas compared with TB structure and achieves better f T and f MAX with respect to smaller parasitic gate-source capacitance. [6] The TDBC structure also shows excellent immunity of back gate bias effect [7] compared with FB and TB devices. Most importantly, the fabrication process of TDBC structure is fully compatible with the usual SOI CMOS technology.…”