Effect of GaN surface treatment on Al2O3/n-GaN MOS capacitors
- Kansas State Univ., Manhattan, KS (United States)
- Naval Research Lab. (NRL), Washington, DC (United States)
- Naval Research Lab. (NRL), Washington, DC (United States).
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
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)(2)S, 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 (0.2nm surface roughness), the lowest carbon concentration (similar to 0.78%) at the Al2O3/n-GaN interface (from x-ray photoelectron spectroscopy), and the lowest oxide-trap charge (Q(T) = 1.6 x 10(11) cm(-2) eV(-1)). Its interface trap density (D-it = 3.7 x 10(12) cm(-2) eV(-1)), as measured with photon-assisted capacitance- voltage method, was the lowest from conduction band-edge to midgap. (C) 2015 American Vacuum Society.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1346638
- Journal Information:
- Journal of vacuum science & technology. B, Microelectronics and nanometer structures, Vol. 33, Issue 6; ISSN 1071-1023
- Country of Publication:
- United States
- Language:
- English
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