Analysis on Trap States in p-Metal-Oxide-Semiconductor Capacitors with Ultraviolet/Ozone-Treated GaN Interfaces Through Frequency-Dispersion Capacitance–Voltage Measurements

• Published in: Electronic materials letters 2020, 16(2), , pp.140-145
• Main Author: Kim, Kwangeun
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Capacitance; Capacitors; Characterization and Evaluation of Materials; Charge density; Chemistry and Materials Science; Condensed Matter Physics; Conduction bands; Dispersion; Electrical measurement; Electrons; Gallium nitrides; Graphical user interface; Magnetics and Photonics; Materials Science; Metal oxide semiconductors; Nanotechnology; Nanotechnology and Microengineering; Optical and Electronic Materials; Original Article - Electronics; Ozone; P-type semiconductors; Photoelectrons; Trapped charge; 전자/정보통신공학
• ISSN: 1738-8090; 2093-6788
• DOI: 10.1007/s13391-019-00194-z

The trap states at ultraviolet/ozone (UV/O 3 )-treated Al 2 O 3 /GaN interfaces of p-type metal-oxide-semiconductor capacitors (pMOSCAPs) are analyzed through a frequency-dispersion capacitance–voltage (C–V) measurements. X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy are applied to confirm a formation of ultrathin oxide layer (Ga 2 O x ) on GaN surface by the UV/O 3 treatment. The trapped charge density and interface trap density improved from 7.30 × 10 11 to 2.79 × 10 11  cm −2  eV −1 averaged over the bandgap of GaN and from 1.28 × 10 13 to 4.08 × 10 12  cm −2  eV −1 near the conduction band edge of GaN, respectively, owing to the passivation of Ga 2 O x layer at the Al 2 O 3 /GaN interfaces. Mechanism for the improved trap states in pMOSCAPs is identified based on the reduced defect states at both Al 2 O 3 /Ga 2 O x and Ga 2 O x /GaN interfaces. Graphic Abstract