Direct observation of 0.57 eV trap-related RF output power reduction in AlGaN/GaN high electron mobility transistors

Abstract This paper reports direct evidence for trap-related RF output power loss in GaN high electron mobility transistors (HEMTs) grown by metal organic chemical vapor deposition (MOCVD) through increased concentration of a specific electron trap at E C −0.57 eV that is located in the drain access region, as a function of accelerated life testing (ALT). The trap is detected by constant drain current deep level transient spectroscopy (CI D -DLTS) and the CI D -DLTS thermal emission time constant precisely matches the measured drain lag. Both drain lag and CI D -DLTS measurements show this state to already exist in pre-stressed devices, which coupled with its strong increase in concentration as a function of stress in the absence of significant increases in concentrations of other detected traps, imply its role in causing degradation, in particular knee walkout. This study reveals E C −0.57 eV trap concentration tracks degradation induced by ALT for MOCVD-grown HEMTs supplied by several commercial and university sources. The results suggest this defect has a common source and may be a key degradation pathway in AlGaN/GaN HEMTs and/or an indicator to predict device lifetime.

[1]  Steven A. Ringel,et al.  Next generation defect characterization in nitride HEMTs , 2011 .

[2]  Seong-Yong Park,et al.  TEM Observation of Crack- and Pit-Shaped Defects in Electrically Degraded GaN HEMTs , 2008, IEEE Electron Device Letters.

[3]  S. A. Ringel,et al.  Spatially-discriminating trap characterization methods for HEMTs and their application to RF-stressed AlGaN/GaN HEMTs , 2010, 2010 International Electron Devices Meeting.

[4]  Steven A. Ringel,et al.  Nm-scale measurements of fast surface potential transients in an AlGaN/GaN high electron mobility transistor , 2012 .

[5]  Shreepad Karmalkar,et al.  Enhancement of breakdown voltage in AlGaN/GaN high electron mobility transistors using a field plate , 2001 .

[6]  U. Mishra,et al.  Identification of electronic traps in AlGaN/GaN HEMTs using UV light-assisted trapping analysis , 2010, 2010 IEEE International Reliability Physics Symposium.

[7]  J.A. del Alamo,et al.  Impact of electrical degradation on trapping characteristics of GaN high electron mobility transistors , 2008, 2008 IEEE International Electron Devices Meeting.

[8]  Aaron R. Arehart,et al.  Investigation of electrically active defects in GaN, AlGaN, and AlGaN/GaN high electron mobility transistors , 2009 .

[9]  G. Verzellesi,et al.  Reliability of GaN High-Electron-Mobility Transistors: State of the Art and Perspectives , 2008, IEEE Transactions on Device and Materials Reliability.

[10]  Paul Saunier,et al.  Physical degradation of GaN HEMT devices under high drain bias reliability testing , 2009, Microelectron. Reliab..

[11]  G. Meneghesso,et al.  Correlation between DC and rf degradation due to deep levels in AlGaN/GaN HEMTs , 2009, 2009 IEEE International Electron Devices Meeting (IEDM).