Electrical Characteristic of AlGaN/GaN High-Electron-Mobility Transistors With Recess Gate Structure

Niraj Man Shrestha, Yi-Ming Li*, Tetsuya Suemitsu, Seiji Samukawa

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


AlGaN/GaN high-electron-mobility transistors (HEMTs) with nonrecess and recess gates are simulated by solving a set of drift-diffusion equations for electrostatic potential and electron-hole concentrations with self-heating model. The approach is first calibrated for both HEMT devices with experimentally measured data, to provide the best accuracy of the simulation. Recess gate device suffers from high potential to the channel, increased parasitic resistances, and deep level traps in barrier due to surface roughness. In addition, selective thinning of the barrier and increase parasitic resistance results in 17% reduction on the carrier concentration. The carrier mobility degradation due to surface roughness and electron velocity lessen due to high electric field result shrinkage of current density with considerable shift of the threshold voltage toward positive value. Even though transconductance does not seems to be remarkably changed for 3-nm recess gate, its value increases on deeper recess. This paper reveals that surface roughness is crucial issue that has dominant role behind the low current density in the recess gate structure. The detail physical understanding of the recess technology will be helpful to minimize the performance deterioration of the explored devices.

Original languageEnglish
Pages (from-to)1694-1698
Number of pages5
JournalIeee Transactions On Electron Devices
Issue number4
StatePublished - Apr 2019


  • High-electron-mobility transistors (HEMTs)
  • mobility
  • neutral beam etching (NBE)
  • recess
  • MODE


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