Reliability evaluation of hermetic GaAs HEMT MMICs using wafer-scale-assembly technology for compact and light-weight applications

Wafer-scale-assembly (WSA) technology has been developed for compact and light-weight applications at the Northrop Grumman Corporation. To insure successful insertion of WSA hermetic MMICs for military and space applications, high-reliability demonstration is essential. In this study, we performed two-temperature lifetesting to evaluate the reliability performance of WSA hermetic GaAs HEMT MMICs. It was observed that gate sinking is still the primary degradation mechanism. In addition, finite-element thermal analysis was performed on the hermetic HEMT MMICs. The results showed an increase in channel temperature over similar non-hermetic GaAs HEMTs of approximately 8degC. The median-time-to-failure (MTF) of approximately 5.6 times 10⁶ hours at T_channel of 125degC was obtained based on reliability analysis with lower bound activation energy (Ea) of 1 eV. This promising result suggests that WSA technology could deliver reliable compact and light-weight HEMT MMICs for military and space applications.