The impact of quantum confinement on the electrical characteristics of ultrathin-channel GeO1 n- MOSFETs is investigated on the basis of the density-gradient model in TCAD software. The effects of the channel thickne...The impact of quantum confinement on the electrical characteristics of ultrathin-channel GeO1 n- MOSFETs is investigated on the basis of the density-gradient model in TCAD software. The effects of the channel thickness （Tch） and back-gate bias （Vbg） on the electrical characteristics of GeOI MOSFETs are examined, and the simulated results are compared with those using the conventional semi-classical model. It is shown that when T^h 〉 8 rim, the electron conduction path of the GeOI MOSFET is closer to the front-gate interface under the QC model than under the CL model, and vice versa when Tch 〈 8 rim. Thus the electrically controlled ability of the front gate of the devices is influenced by the quantum effect. In addition, the quantum-mechanical mechanism will enhance the drain-induced barrier lowering effect, increase the threshold voltage and decrease the on-state current; for a short channel length （≤ 30 nm）, when Tch 〉 8 nm （or 〈 8 nm）, the quantum-mechanical mechanism mainly impacts the subthreshold slope （or the threshold voltage）. Due to the quantum-size effect, the off-state current can be suppressed as the channel thickness decreases.展开更多
基金supported by the National Natural Science Foundation of China(No.61274112)
文摘The impact of quantum confinement on the electrical characteristics of ultrathin-channel GeO1 n- MOSFETs is investigated on the basis of the density-gradient model in TCAD software. The effects of the channel thickness （Tch） and back-gate bias （Vbg） on the electrical characteristics of GeOI MOSFETs are examined, and the simulated results are compared with those using the conventional semi-classical model. It is shown that when T^h 〉 8 rim, the electron conduction path of the GeOI MOSFET is closer to the front-gate interface under the QC model than under the CL model, and vice versa when Tch 〈 8 rim. Thus the electrically controlled ability of the front gate of the devices is influenced by the quantum effect. In addition, the quantum-mechanical mechanism will enhance the drain-induced barrier lowering effect, increase the threshold voltage and decrease the on-state current; for a short channel length （≤ 30 nm）, when Tch 〉 8 nm （or 〈 8 nm）, the quantum-mechanical mechanism mainly impacts the subthreshold slope （or the threshold voltage）. Due to the quantum-size effect, the off-state current can be suppressed as the channel thickness decreases.
