The Dependence of off-State Breakdown of AlGaN/GaN HEMTs on Buffer Traps, Gate Bias and Field Plate

  • Sukalpa MishraEmail author
  • Sudipto Bhattacharya
  • D. S. Rawal
  • S. Karmalkar
Conference paper
Part of the Springer Proceedings in Physics book series (SPPHY, volume 215)


We investigate AlGaN/GaN HEMTs which show a large increase in measured off-state breakdown voltage, VBR, from near-VT to deep-off state VGS conditions, accompanied by a positive shift in measured VT, when these devices are stressed electrically by alternating IDVGS and IDVDS measurements. We show that, if stress is assumed to cause spatially uniform changes, the above variations in VBR and VT can be explained in terms of increased ionized deep acceptor trap concentration in the GaN buffer. We also show that, the near-VT VBR is due to space-charge limited current while the deep off-state VBR is due to impact ionization. Our simulations predict that the incorporation of a field plate in the device can enhance the latter VBR significantly, but may not change the former VBR much.



We thank B. Prasannanjaneyulu for helpful discussions.


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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  • Sukalpa Mishra
    • 1
    Email author
  • Sudipto Bhattacharya
    • 2
  • D. S. Rawal
    • 3
  • S. Karmalkar
    • 1
  1. 1.Electrical Engineering DepartmentIndian Institute of Technology MadrasChennaiIndia
  2. 2.Research and Innovation CentreIIT Madras Research ParkChennaiIndia
  3. 3.Solid State Physics LaboratoryTimarpur, New DelhiIndia

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