Unusual gate coupling effect in extremely thin and short FDSOI MOSFETs

Display Omitted Ultra-thin film FDSOI MOSFETs have been investigated for various film thicknesses, gate lengths, back-gate biases and temperature.High carrier mobility and excellent subthreshold swing was achieved thanks to the state-of-the-art technology.The relationship between the film thickness, temperature, and coupling effect was explored.In short-channel FDSOI device, coupling effect increases with raising temperature.In devices thinner than 5-6nm, the coupling is independent of temperature due to the minimized short-channel effects. We investigated the characteristics of state-of-the-art FDSOI MOSFETs in a wide range of temperature by focusing on the effects of the back-gate bias, Si film thickness and channel length. High device performance and remarkably reduced short-channel effect with decreasing Si film thickness are achieved in ultra-thin film SOI devices. Systematic measurements reveal an unusual coupling effect resulting from the competition between front-gate, back-gate and temperature-dependent short-channel effect. Counter-intuitively, the impact of the back-gate bias can be smaller in 5nm than in 10nm thick MOSFETs, in particular in very short devices operated at 300K.