Performance Analysis of Signal Characteristics of MODFET

Vol. 2 No.2

Year: 2013

Issue: May-Jul

Title : Performance Analysis of Signal Characteristics of MODFET

Author Name : Ganesan.V, K.S. Shaji

Synopsis :

This work addresses the scalability of power performance of AlGaAs/GaAs MODFET (modulated-Doping Field Effect Transistor) with large gate periphery, as necessary for microwave power devices. High-frequency large signal characteristics of AlGaAs/GaAs MODFET have been studied for devices with gate widths from 0.2 to 1 mm. 1-dB gain compression occurred at input power levels varying from -1 to +10dBm as the gate width increased, while gain remained almost constant at ~17dB. Output power density was maximum (1.3W/mm) for devices with 0.6mm gates and maximum output power (29.9dBm) occurred in devices with 1mm gates, while power-added-efficiency remained almost constant at ~30%.We also present a model for the I-V characteristics of MODFET's. In this paper, an analytic velocity-field model is used. To more accurately describe the physical characteristics of MODFET's the model of this paper is divided into two regions (the linear region and the saturation region), being continuous at the pinchoff voltage, and includes the diffusion component in addition to the drift component of current. Using this model, the simulated I-V characteristics are in excellent agreement with the experimental data.