Impact of Trapping Effects on the Recovery Time of GaN Based Low Noise

Artikel i vetenskaplig tidskrift, 2016

This study investigates recovery time of the gain of AlGaN/GaN HEMT    based low noise amplifiers (LNA) after an input overdrive pulse. Three    LNAs, fabricated in two commercial MMIC processes and a Chalmers    in-house process, are evaluated. The Chalmers process has an    unintentionally doped buffer instead of the intentional Fe doping of the    buffer which is standard in commercial GaN HEMT technologies. It is    shown that the LNAs from the two commercial processes experience a    severe drop in gain after input overdrive pulses higher than 28 dBm,    recovering over a duration of around 20 ms. In contrast the LNA    fabricated in-house at Chalmers experienced no visible effects up to an    input power of 33 dBm. These results have impact for radar and    electronic warfare receivers, which need to be operational immediately    after an overdrive pulse. The long time constants suggest that these    effects are due to trapping in the transistors with the Fe doped buffer    playing an important role.