Deep-Level Traps in AlGaN/GaN- And AlInN/GaN-Based HEMTs with Different Buffer Doping Technologies

P. Vigneshwara Raja*, Mohamed Bouslama, Sujan Sarkar, Khade Ramdas Pandurang, Jean Christophe Nallatamby, Nandita Dasgupta, Amitava Dasgupta

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Deep-level traps in AlGaN/GaN- and AlInN/GaN-based HEMTs with different buffer doping technologies are identified by drain current transient spectroscopy (DCTS) and low-frequency (LF) output admittance ( {Y}_{{22}} ) dispersion techniques. TCAD simulations are also carried out to determine the spatial location and type of traps. The DCTS and LF {Y}_{{22}} measurements on Al0.25Ga0.75N/GaN HEMT (Fe-doped buffer) reveal a single electron trap at {E}_{C} - {0.47} eV. On the other hand, an electron trap at {E}_{C} - (0.53-0.59) eV and a deep hole trap at {E}_{V} + {0.82} eV are detected in Al0.845In0.155N/AlN/GaN HEMT with unintentionally doped (UID) buffer, while a slow detrapping behavior is noticed at {E}_{C} - {0.6} eV in Al0.83In0.17N/AlN/GaN HEMT with C-doped buffer. The DCTS and LF {Y}_{{22}} measurements yield nearly the same trap signatures, indicating the reliability of the trap characterization techniques used in this article. The simulated LF {Y}_{{22}} characteristics show that all these traps are acceptor-like states located in the buffer layer. The identified trap parameters in various buffers may be helpful to improve the crystalline quality of the epitaxial buffer layers.

Original languageEnglish
Article number9082823
Pages (from-to)2304-2310
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number6
StatePublished - Jun 2020


  • Buffer doping
  • Current transient
  • GaN HEMT
  • Output admittance
  • TCAD simulation
  • Traps


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