Search

This paper investigates the impact of quantum confinement (QC) on the backgate-bias (Vbg) modulated subthreshold and threshold-voltage (Vth) characteristics of ultra-thin-body germanium-on-insulator (UTB GeOI) MOSFETs using an analytical solution of the Schrödinger equation verified with TCAD numerical simulation. Our study indicates that the QC effect reduces the sensitivity of the subthreshold swing to Vbg. In addition, the sensitivity of Vth to Vbg can be enhanced by the QC effect particularly for electrostatically well-behaved UTB MOSFETs with triangular potential well. Aside from that, the sensitivity of Vth roll-off to Vbg is reduced by the QC effect. Since Ge and Si channels exhibit different degrees of QC due to different quantization effective mass, the impact of QC has to be considered when one-to-one comparisons between GeOI and SOI MOSFETs regarding the backgate-bias modulated threshold-voltage and subthreshold characteristics are made. Our study may provide insights for multi- Vth device/circuit designs using advanced UTB GeOI technologies. [ABSTRACT FROM PUBLISHER]

This paper provides a closed-form model of the “dark space (DS)” for Ge MOSFETs with high- k gate dielectrics. This model shows accurate dependences on barrier height, surface electric field, and quantization effective mass of the channel and gate dielectric. Our model predicts that the surface DS due to quantum confinement decreases with reverse substrate bias and increasing channel doping. Our model can be also used for devices with a steep retrograde doping profile. This physically accurate model will be crucial to the prediction of the subthreshold swing and electrostatic integrity of advanced Ge devices. [ABSTRACT FROM AUTHOR]

This paper investigates the electrostatic integrity (EI) of ultra-thin-body (UTB) germanium-on-insulator (GeOI) and InGaAs-OI n-MOSFETs considering quantum confinement (QC) using a derived analytical solution of Schrödinger equation verified with TCAD numerical simulation. Although the electron conduction path of the high-mobility channel device can be far from the frontgate interface due to high channel permittivity, our study indicates that the quantum confinement effect can move the carrier centroid toward the frontgate and, therefore, improve the subthreshold swing (SS) of the UTB device. Since InGaAs, Ge, and Si channels exhibit different degrees of quantum confinement due to different quantization effective mass, the impact of quantum confinement has to be considered when one-to-one comparisons among UTB InGaAs-OI, GeOI, and SOI MOSFETs regarding the subthreshold swing and electrostatic integrity are made. [ABSTRACT FROM PUBLISHER]

This letter investigates the impact of quantum confinement (QC) on the short-channel effect (SCE) of ultrathin-body (UTB) and thin-buried-oxide germanium-on-insulator (GeOI) MOSFETs using an analytical solution of Schrödinger equation verified with TCAD simulation. Our study indicates that, although the QC effect increases the threshold voltage (Vth) roll-off when the channel thickness (Tch) is larger than a critical value (Tch, crit), it may decrease the Vth roll-off of GeOI MOSFETs when the Tch is smaller than Tch, crit. Since Ge and Si channels exhibit different degrees of confinement and Tch, crit, the impact of QC must be considered when one-to-one comparisons between UTB GeOI and Si-on-insulator MOSFETs regarding the SCE are made. [ABSTRACT FROM AUTHOR]