A Universal Large-Signal Model for Hetero Field Effect Transistors (original) (raw)
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IEEE Transactions on Electron Devices, 1999
We describe a new enhanced model for deep submicron heterostructure field effect transistors (HFET's) suitable for implementation in computer aided design (CAD) software packages such as SPICE. The model accurately reproduces both above-threshold and subthreshold characteristics of both nand p-channel deep submicron HFET's over the temperature range 250-450 K. The current-voltage (I0V ) characteristics are described by a single, continuous, analytical expression for all regimes of operation, thereby improving convergence. The physics-based model includes effects such as velocity saturation in the channel, drain-induced barrier lowering (DIBL), finite output conductance in saturation, frequency dispersion, and temperature dependence. The output resistance and the transconductance are accurately reproduced, making the model suitable for simulation of mixed mode (digital/analog) circuits. The model has been extensively verified against experimental data for two HFET technologies with gate lengths down to 0.3 m.
A user compiled large signal model for GaAs heterojunction bipolar transistors
This paper presents a nonlinear circuit simulation model for III-V Heterojunction Bipolar Transistors (HBTs), implemented using C code in the Agilent ADS circuit simulator as a User Compiled Model (UCM). The UCM is based-on a recently developed compact large-signal model, which includes all physical effects taking place in power III-V based HBT devices. The validity and the accuracy of the UCM are assessed by comparing its simulation results to both measurements and Symbolically Define Device (SDD) simulations in DC, multibias small-signal S-parameters and large-signal microwave power characteristics for a 2x20 m 2 emitter area InGaP/GaAs transistor.
Heterostructure field effect transistors (HFETs) are based on AlGaN/GaN heterostructures which offer excellent electronic properties for the development of faster, heat-resistant , energy efficient transistors and application in microwavepower amplifiers [1,2]. The outstanding device performance in cut-off frequency, breakdown voltage, and device output power . However, the comparatively analysis of small signal and large signal parameters which are seldom found in this paper.
A simplified broad-band large-signal nonquasi-static table-based FET model
IEEE Transactions on Microwave Theory and Techniques, 2000
In this paper, a simplified nonquasi-static table-based approach is developed for high-frequency broad-band large-signal field-effect-transistor modeling. As well as low-frequency dispersion, the quadratic frequency dependency of the -parameters at high frequencies is taken into account through the use of linear delays. This model is suitable for applications related with nonlinear microwave computer-aided design and can be both easily extracted from dc and -parameter measurements and implemented in commercially available simulation tools. Model formulation, small-signal, and large-signal validation will be described in this paper. Excellent results are obtained from dc up to the device frequencies, even when is as high as 100 GHz.
Monte Carlo simulation of short channel heterostructure field-effect transistors
IEEE Transactions on Electron Devices, 1991
Using self-consistent Monte Carlo simulation we study selfaligned, planar-doped AIGaAs/GaAs Heterostructure Field-Effect Transistors (HFET's) with gate lengths varying from 0.1 to 1.0 pm, and two different depths of the implanted contacts. The drain output conductance in saturation as well as the threshold voltage shift are found to be approximately inversely proportional to the square of the gate length for gate lengths smaller than 0.5 Wm. The predominant physical mechanism behind these short-channel effects at such gate lengths is the injection of electrons from the contacts into the GaAs buffer region beneath the two-dimensional channel. The critical parameter for the onset of large short-channel effects is the ratio between the source region-drain region separation and the contact depth. Hence, an optimum depth of the contacts should he found as a traded between short-channel effects and parasitic series resistances. Simulated current-voltage characteristics exhibit pronounced negative differential resistance at large gate voltages because of real space transfer of channel electrons into the AlGaAs layer and subsequent collection by the gate electrode. Simulated on and off transients have similar durations, but a trend toward shorter switch-off times exists.
Analytical gate current model for n-channel heterostructure field effect transistors
IEEE Transactions on Electron Devices, 1998
A simple analytical gate current model for n-channel heterostructure field effect transistors (HFET's) has been developed. Our model is based on the self-consistent approximation to the solution of Schrödinger and Poisson's equations, and the theory of thermionic-field emission. Good agreement between the experimental data and the model results is obtained over the entire range of gate voltages, from below to above threshold, and over a wide range of temperature from 198 to 450 K. Only four parameters are used to fit the experimental data with two of these parameters obtained from the experimental results. This model is suitable for implementation in sophisticated CAD tools such as SPICE.