Uniformity investigation of pHEMTs in 3-D MMICs for pre and post multilayer fabrication

Abstract

This study deals with the uniformity investigation and comparison on the typical behaviour of pseudomorphic high electron mobility transistors (pHEMTs) before and after the 3-D multilayer fabrication. There are seven multilayer fabricated pHEMTs compared with the seven virgin pHEMTs based on drain-source input current, output current, transconductance, off state leakage behaviour, threshold voltage, knee voltage, on-resistance, Schottky barrier height, ideality factor, reverse saturation current, small signal gain and current gain. Below 10% changes in performance can be seen after multilayer fabrication compare to virgin samples and apart from these exceptions, the discrepancies are well within the tolerance and less than 3% in terms of Schottky behaviour. We show that, the application of the 3D-MMIC technology does not cause any visible destruction of pHEMTs performance using seven different samples before and after the multilayer fabrication.