ANALYSIS OF A RADIO FREQUENCY TRANSIMPEDANCE AMPLIFIER BASED ON A δ-DOPED AlInAs-GaInAs HEMT AND ITS PERFORMANCE OPTIMIZATION

摘要

A simple approach has been proposed for the optimization of performance parameters such as transimpedance-bandwidth product, transition frequency f_T and maximum frequency of oscillation f_(max) of high electron mobility transistors (HEMTs). The radio frequency (RF) small-signal equivalent circuit model has been employed to represent the ac behavior of T-shape gate AlInAs-GaInAs δ-doped HEMTs. All the circuit parameters pertaining to the model have been determined as a function of the width W of the device and surface density of charge δ in the channel. Then PSpice has been used to simulate the device. Good agreement between experimental and simulated values of |h_(fe)|~2 versus frequency is obtained. The same model is then employed to optimize performance parameters of the HEMT and the MSM-HEMT amplifier with reference to width and surface density of charge δ in the channel.