Effect of GaN surface treatment on Al2O3/n-GaN MOS capacitors
Abstract
The surface preparation for depositing Al2O3 for fabricating Au/Ni/Al2O3/n-GaN (0001) metal oxide semiconductor (MOS) capacitors was optimized as a step toward realization of high performance GaN MOSFETs. The GaN surface treatments studied included cleaning with piranha (H2O2:H2SO4 = 1:5), (NH4)2S, and 30% HF etches. By several metrics, the MOS capacitor with the piranha-etched GaN had the best characteristics. It had the lowest capacitance–voltage hysteresis, the smoothest Al2O3 surface as determined by atomic force microscopy (0.2 nm surface roughness), the lowest carbon concentration (∼0.78%) at the Al2O3/n-GaN interface (from x-ray photoelectron spectroscopy), and the lowest oxide-trap charge (QT = 1.6 × 1011 cm−2eV−1). Its interface trap density (Dit = 3.7 × 1012 cm−2eV−1), as measured with photon-assisted capacitance– voltage method, was the lowest from conduction band-edge to midgap.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 25, 2015
- Source ID
- 10.1116/1.4931793
Entities
People
- Charles. R. Eddy Jr.
- Daming Wei
- Harry M. Meyer Iii
- James H Edgar
- Jennifer K Hite
- Michael A. Mastro
- Neeraj Nepal
- Nelson Y. Garces
- Tashfin Hossain
Organizations
- Kansas State University
- Oak Ridge National Laboratory
- Office of Naval Research
- United States Naval Research Laboratory