[6p-A301-1~7] Materials Science and Advanced Electronics Created by Singularity of Nitride Semiconductors ~Crystal Growth, Characterization and Application for Advanced GaN Electron Devices~

[6p-A301-7] MOVPE growth of InAlN HEMT structures and suppression of gate leakage current
based on the control of internal electric field

〇Junji Kotani¹, Atsushi Yamada¹, Norikazu Nakamura¹ (1.Fujitsu Ltd.)

Keywords:GaN, InAlN, Leakage current

This paper investigate the effects of threading dislocation density on the leakage characteristics of Ni/Au Schottky diodes fabricated on InAlN high-electron-mobility transistor (HEMT) structures. Threading dislocation densities were determined to be 1.8 x 10⁴ cm^-2 and 1.2 x 10⁹ cm^-2 for the HEMT structures grown on GaN and sapphire substrates, respectively. Leakage characteristics of Ni/Au Schottky diodes were compared between the two samples and a reduction of the leakage current of about three to four orders of magnitude was observed in the forward bias region. For the high reverse bias region, however, no significant improvement was confirmed. We believe the leakage current in the low bias region is governed by a dislocation-related Frenkel-Poole emission and the leakage current in the high reverse bias region originates from field emission due to the large internal electric field in the InAlN barrier layer.