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Title: Degradation and annealing effects caused by oxygen in AlGaN/GaN high electron mobility transistors

Abstract

Hot-carrier degradation and room-temperature annealing effects are investigated in unpassivated ammonia-rich AlGaN/GaN high electron mobility transistors. Devices exhibit a fast recovery when annealed after hot carrier stress with all pins grounded. The recovered peak transconductance can exceed the original value, an effect that is not observed in control passivated samples. Density functional theory calculations suggest that dehydrogenation of pre-existing O{sub N}-H defects in AlGaN plays a significant role in the observed hot carrier degradation, and the resulting bare O{sub N} can naturally account for the “super-recovery” in the peak transconductance.

Authors:
; ; ; ;  [1];  [2];  [3];  [1];  [3]; ; ;  [4];  [2];  [3]
  1. Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennesse 37235 (United States)
  2. Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennesse 37235 (United States)
  3. (United States)
  4. Materials Department, University of California, Santa Barbara, California 93106 (United States)
Publication Date:
OSTI Identifier:
22590614
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 109; Journal Issue: 2; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMMONIA; ANNEALING; DEHYDROGENATION; DENSITY FUNCTIONAL METHOD; ELECTRON MOBILITY; GALLIUM NITRIDES; STRESSES; TEMPERATURE RANGE 0273-0400 K; TRANSISTORS

Citation Formats

Jiang, R., E-mail: rong.jiang@vanderbilt.edu, Chen, J., Duan, G. X., Zhang, E. X., Schrimpf, R. D., Shen, X., Department of Physics and Materials Science, University of Memphis, Memphis, Tennesse 38152, Fleetwood, D. M., Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennesse 37235, Kaun, S. W., Kyle, E. C. H., Speck, J. S., Pantelides, S. T., and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennesse 37235. Degradation and annealing effects caused by oxygen in AlGaN/GaN high electron mobility transistors. United States: N. p., 2016. Web. doi:10.1063/1.4958706.
Jiang, R., E-mail: rong.jiang@vanderbilt.edu, Chen, J., Duan, G. X., Zhang, E. X., Schrimpf, R. D., Shen, X., Department of Physics and Materials Science, University of Memphis, Memphis, Tennesse 38152, Fleetwood, D. M., Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennesse 37235, Kaun, S. W., Kyle, E. C. H., Speck, J. S., Pantelides, S. T., & Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennesse 37235. Degradation and annealing effects caused by oxygen in AlGaN/GaN high electron mobility transistors. United States. doi:10.1063/1.4958706.
Jiang, R., E-mail: rong.jiang@vanderbilt.edu, Chen, J., Duan, G. X., Zhang, E. X., Schrimpf, R. D., Shen, X., Department of Physics and Materials Science, University of Memphis, Memphis, Tennesse 38152, Fleetwood, D. M., Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennesse 37235, Kaun, S. W., Kyle, E. C. H., Speck, J. S., Pantelides, S. T., and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennesse 37235. Mon . "Degradation and annealing effects caused by oxygen in AlGaN/GaN high electron mobility transistors". United States. doi:10.1063/1.4958706.
@article{osti_22590614,
title = {Degradation and annealing effects caused by oxygen in AlGaN/GaN high electron mobility transistors},
author = {Jiang, R., E-mail: rong.jiang@vanderbilt.edu and Chen, J. and Duan, G. X. and Zhang, E. X. and Schrimpf, R. D. and Shen, X. and Department of Physics and Materials Science, University of Memphis, Memphis, Tennesse 38152 and Fleetwood, D. M. and Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennesse 37235 and Kaun, S. W. and Kyle, E. C. H. and Speck, J. S. and Pantelides, S. T. and Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, Tennesse 37235},
abstractNote = {Hot-carrier degradation and room-temperature annealing effects are investigated in unpassivated ammonia-rich AlGaN/GaN high electron mobility transistors. Devices exhibit a fast recovery when annealed after hot carrier stress with all pins grounded. The recovered peak transconductance can exceed the original value, an effect that is not observed in control passivated samples. Density functional theory calculations suggest that dehydrogenation of pre-existing O{sub N}-H defects in AlGaN plays a significant role in the observed hot carrier degradation, and the resulting bare O{sub N} can naturally account for the “super-recovery” in the peak transconductance.},
doi = {10.1063/1.4958706},
journal = {Applied Physics Letters},
number = 2,
volume = 109,
place = {United States},
year = {Mon Jul 11 00:00:00 EDT 2016},
month = {Mon Jul 11 00:00:00 EDT 2016}
}
  • In this paper, we investigate the degradation mode and mechanism of AlGaN/GaN based high electron mobility transistors (HEMTs) during high temperature operation (HTO) stress. It demonstrates that there was abrupt degradation mode of drain current during HTO stress. The abrupt degradation is ascribed to the formation of crack under the gate which was the result of the brittle fracture of epilayer based on failure analysis. The origin of the mechanical damage under the gate is further investigated and discussed based on top-down scanning electron microscope, cross section transmission electron microscope and energy dispersive x-ray spectroscopy analysis, and stress simulation. Basedmore » on the coupled analysis of the failure physical feature and stress simulation considering the coefficient of thermal expansion (CTE) mismatch in different materials in gate metals/semiconductor system, the mechanical damage under the gate is related to mechanical stress induced by CTE mismatch in Au/Ti/Mo/GaN system and stress concentration caused by the localized structural damage at the drain side of the gate edge. These results indicate that mechanical stress induced by CTE mismatch of materials inside the device plays great important role on the reliability of AlGaN/GaN HEMTs during HTO stress.« less
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  • The recovery effects of thermal annealing on dc and rf performance of off-state step-stressed AlGaN/GaN high electron mobility transistors were investigated. After stress, reverse gate leakage current and sub-threshold swing increased and drain current on-off ratio decreased. However, these degradations were completely recovered after thermal annealing at 450 °C for 10 mins for devices stressed either once or twice. The trap densities, which were estimated by temperature-dependent drain-current sub-threshold swing measurements, increased after off-state step-stress and were reduced after subsequent thermal annealing. In addition, the small signal rf characteristics of stressed devices were completely recovered after thermal annealing.
  • The effects of proton irradiation energy on dc, small signal, and large signal rf characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) were investigated. AlGaN/GaN HEMTs were irradiated with protons at fixed fluence of 51015/cm2 and energies of 5, 10, and 15 MeV. Both dc and rf characteristics revealed more degradation at lower irradiation energy, with reductions of maximum transconductance of 11%, 22%, and 38%, and decreases in drain saturation current of 10%, 24%, and 46% for HEMTs exposed to 15, 10, and 5MeV protons, respectively. The increase in device degradation with decreasing proton energy is due to the increasemore » in linear energy transfer and corresponding increase in nonionizing energy loss with decreasing proton energy in the active region of the HEMTs. After irradiation, both subthreshold drain leakage current and reverse gate current decreased more than 1 order of magnitude for all samples. The carrier removal rate was in the range 121 336 cm1 over the range of proton energies employed in this study« less