We compare the performance of GaN HEMT devices based on the established Ga-face technology and the emerging N-face technology. Starting from a state-of-the-art N-face device, we obtain the analogous Ga-face layout imposing the constraint of the same channel charge in both structures, and then, we simulate both the configurations with our full-band cellular Monte Carlo simulator, which includes the full details of the band structure and the phonon spectra. Moreover, we define a modeling approach based on gate-to-2-D electron gas distance and capacitance discussions, which allows a fair comparison between the N- and Ga-face technologies. Full direct current and RF simulations were performed and compared with available experimental data for the N-face device in order to calibrate the few adjustable simulator parameters. Our simulations indicate that N-face GaN HEMTs exhibit improved RF performance with respect to Ga-face devices. Furthermore, the use of an AlN layer in N-face devices results in a reduced alloy scattering and offers a strong back-barrier electron confinement to mitigate short-channel effects, thus improving the cutoff frequency for highly scaled devices.

Original languageEnglish (US)
Article number5595023
Pages (from-to)3348-3354
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number12
StatePublished - Dec 2010


  • GaN
  • Monte Carlo
  • N-face
  • high frequency
  • high-electron mobility transistors (HEMT)
  • numerical simulation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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