Time Dependent Shift in SOA Boundary and Early Breakdown of Epi-Stack in AlGaN/ GaN HEMTs under Fast Cyclic Transient Stress

Shankar, B and Shikha, S and Singh, A and Kumar, J and Soni, A and Dutta Gupta, S and Raghavan, S and Shrivastava, M (2020) Time Dependent Shift in SOA Boundary and Early Breakdown of Epi-Stack in AlGaN/ GaN HEMTs under Fast Cyclic Transient Stress. In: IEEE Transactions on Device and Materials Reliability, 20 (3). pp. 562-569.

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Abstract

This experimental study reports first observations of (i) SOA boundary shift in AlGaN/GaN HEMTs and (ii) early time-to-fail of vertical AlGaN/GaN epi-stack under fast changing (sub-10ns rise time) cyclic pulse transient stress, which otherwise qualified for 600 V DC stress. It is shown that a epi stack qualified for 10 years lifetime under DC stress, fails faster under cyclic transient stress. The drain-to-substrate leakage exhibits different trends under DC and pulse stress. Integrated electrical and mechanical stress characterization routine involving Raman/ PL mapping, PFM and CL spectroscopy along with atomistic simulations reveals material limited unique failure physics under transient stress condition. Failure analysis using cross-sectional SEM and TEM investigations reveal signature of different degradation and failure mechanism under transient and DC stress conditions. A failure model is proposed for rapid breakdown of AlGaN/GaN epi-stack under cyclic transient stress and it is experimentally validated.

Item Type:	Journal Article
Publication:	IEEE Transactions on Device and Materials Reliability
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	The copyright for this article belongs to Institute of Electrical and Electronics Engineers Inc.
Keywords:	Aluminum gallium nitride; Failure (mechanical); Gallium nitride; III-V semiconductors, AlGaN/GaN HEMTs; Atomistic simulations; Boundary shifts; Cross-sectional SEM; Cyclic transients; Failure mechanism; Mechanical stress; Transient stress, Stresses
Department/Centre:	Division of Electrical Sciences > Electronic Systems Engineering (Formerly Centre for Electronic Design & Technology) Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	14 Feb 2023 08:57
Last Modified:	14 Feb 2023 08:57
URI:	https://eprints.iisc.ac.in/id/eprint/80241

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