Reliability testing of InP HEMT's using electrical stress methods

Abstract

In this paper, we discuss the results of three different electrical stress tests on InP-based HEMT's and their implications toward reliability. These are hot electron (HE) stress, transmission line pulse (TLP) measurements, and RF overdrive stress. Some processing parameters have been varied to investigate their influence on reliability issues. HE stress is performed on a set of Si 3 N 4 passivated devices with increasing recess width. Degradation is observed to be largely dependent on recess width, due to changes at the InAlAs-Si 3 N 4 interface. With TLP measurements, an ESD-like reliability study is performed on devices with different types of Schottky barriers. Although epilayers with In0:40Al0:60 as Schottky material show improved breakdown and leakage characteristics over In0:52Al0:48As, pulsed stress tests reveal an earlier breakdown. Finally, the degradation under large-signal RF overdrive stress is determined with a nonlinear network measurement system (NNMS). Both on-and off-state degradation are studied with this setup. Results appeared to be strongly dependent on the phase difference between the stress voltage waves applied at the device ports.

Development of an RF IV waveform based stress test procedure for use on GaN HFETs

“…This provided a much greater understanding of the nature of the device degradation. However this approach can be improved by the use of an RF IV waveform measurement system, which measures the RF voltages and currents at the input and output terminals of the device, allowing the exact state of the device to be known during the stress period [5,8]. Here we extend this approach to produce a more complex step stress test [9].…”

“…Alternatively the second solution is to carry out the measurements at the intended operating frequency and then to use a de-embedding process to remove the displacement current caused by the drain-source capacitance (C DS ). This is the solution that we have used, along with several others [5][6][7], for the measurements presented in this paper and our previous work [8][9].…”