New papers about compact modeling

A number of interesting papers have been published in the August issue of Transactions on Electron Devices.

In a paper entitled "Accuracy of Surface-Potential-Based Long–Wide-Channel Thick-Base MOS Transistor Models", Bin B. Jie and Chih-Tang Sah (University of Florida, Gainesville) discuss the accuracy of several surface-potential based MOSFET models. They show that the accuracy of the approximations done in these models is not so good in the accumulation and subthreshold regimes, and they propose a new analytical model showing better accuracy in those regimes.

Ananda S. Roy, Christian C. Enz and J. -M. Sallese, researchers from the EKV team at EPFL (Lausanne, Switzerland) present an analytical noise modeling paradingm for lateral nonuniform MOSFETs. They show that in these devices the bias dependence of the noise parameters cannot be predicted by conventional Klaassen-Prins (KP)-based methods.

Modeling of irradiated devices is always a hot topic. H. T. Mebrahtu et al. present SPICE models of Fluorine-Ion irradiated CMOS devices, using the EKV MOSFET model as a basis.

In this issue we also find new modeling work on Double-Gate MOSFETs. Researchers from the University of Thessaloniki (Greece) and MINATEC (Grenoble, France) have presented a paper entitled "Semi-Analytical Modeling of Short-Channel Effects in Si and Ge Symmetrical Double-Gate MOSFETs". The doping is considered in this work. The analysis is carried out in the subthershold regime, and the mobile charge is assumed to be negligible compared to the doping charge. The model shows that Ge Double-Gate MOSFETs are more prone to short-channel effects than Si Double-Gate MOSFETs.

Finally, B. Bindu, N. DasGupta and A. DasGupta (Indian Institute of Technology, Madras) present "A Unified Model for Gate Capacitance–Voltage Characteristics and Extraction of Parameters of Si/SiGe Heterostructure pMOSFETs". This analytical model is physically-based, and shows very good agreement with experimental measurements.

Atomistic simulation of Graphene Nanoribbon Field-Effect Transistors

A very interesting paper presenting a 3-D atomistic simulation study of Graphene Nanoribbon Field-Effect Transistors (GNR-FETs) has been published in IEEE Electron Device Letters. The performance observed is comparable to the one of carbon nanotube FETs, but the leakage problems associated to the band-to-band tunneling current are also similar. The authors of this paper are B. Fiori and G. Iannacone, from the University of Pisa, Italy.

The simulations have been based on a self-consistent solution of the 3-D Poisson's and Schrödinger equations with open boundary conditions within the nonequilibrium Green's function formalism. This simulation study can be very helpful to start the development of a compact GNR-FET model, which will be necessary if this novel device becomes successful.