A dual-material-gate junctionless nanowire transistor (DMG-JNT) is proposed in this paper. Its characteristic is demonstrated and compared with a generic single-material-gate JNT using 3-D numerical simulations. The results show that the DMG-JNT has a number of desirable features, such as high ON-state current, a large ON/OFF current ratio, improved transconductance G_m, high unity-gain frequency f_T, high maximum oscillation frequency f_MAX, and reduced drain-induced barrier lowering. The effects of different control gate ratios Ra and varied work-function differences between the two gates are studied. Finally, the optimization of Ra and the work-function difference for the proposed DMG-JNT is presented.

An analytical charge model for double gate (DG) tunnel FETs (TFETs) is proposed. By splitting the TFET into a series combination of a gated tunnel diode and a DG MOSFET, we solved the Poisson equation with matching boundary conditions to obtain a surface potential model for the DG TFET. Based on that, the source depletion charge and the mobile channel charge are derived. Comparisons between the proposed model and TCAD simulations show good agreements and suggest a 100/0 drain/source channel inversion charge partition. Terminal capacitances calculated based on the proposed charge model are also evaluated and show good agreement with TCAD simulations.

In this paper, a surface potential-based terminal charge and capacitance model, including parasitic components for AlGaN/GaN HEMTs is developed. First, by solving the charge control equations, the sheet charge density in the channel is modeled with a close-form expression. Then, using this result, based on the surface potential definition, the intrinsic terminal charges and capacitances are derived consistently with current model. Finally, by introducing parasitic components, the capacitances for the full structure of the HEMT devices are given. The model is evaluated step-by-step with good agreements compared with the TCAD simulations and the experimental data. Meanwhile, the effects of bulk traps and surface traps in the capacitances are analyzed. The complete model, including currents and capacitances has been implemented in i-MOS platform for evaluations and circuit simulations.

A charge-based model is presented for long-channel cylindrical surrounding-gate (SRG) MOSFETs from an intrinsic channel to a heavily doped body. The model derivation is based on an accurate inversion charge solution of Poisson's equation in a cylindrical coordinate system. The general drain-current equation is obtained from Pao-Sah's dual integral, which is expressed as a function of inversion charge at the source and drain terminals. The model is valid for all regions of operation without employing any smoothing function. The model has been extensively verified by numerical simulations with a wide range of SRG MOSFET geometry parameters and channel doping concentrations, including the undoped channel.

A compact model for tunneling field-effect-transistors (TFETs) is presented. The model includes a band-to-band tunneling (BTBT) current module and a terminal charge module. TCAD simulations show that the model describes TFETs currents and capacitances accurately. The model is implemented into a circuit simulator and used to simulate TFETs logic circuits and SRAMs. Unique features in TEFTs including large overshoot during switching, long delay and uni-directional conduction are demonstrated.