Interface Properties of Al2O3/n-GaN Structures with Inductively Coupled Plasma Etching of GaN Surfaces

The effects of the Cl 2 -based inductively coupled plasma (ICP) etching of GaN on the interface properties of Al 2 O 3 /GaN structures prepared by atomic layer deposition (ALD) were investigated. We used n-GaN layers grown on freestanding n + -GaN substrates with low dislocation density. The ICP etc...

Full description

Saved in:
Bibliographic Details
Published inJpn J Appl Phys Vol. 51; no. 6; pp. 060201 - 060201-3
Main Authors Kim, Sungsik, Hori, Yujin, Ma, Wang-Cheng, Kikuta, Daigo, Narita, Tetsuo, Iguchi, Hiroko, Uesugi, Tsutomu, Kachi, Tetsu, Hashizume, Tamotsu
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.06.2012
Online AccessGet full text

Cover

More Information
Summary:The effects of the Cl 2 -based inductively coupled plasma (ICP) etching of GaN on the interface properties of Al 2 O 3 /GaN structures prepared by atomic layer deposition (ALD) were investigated. We used n-GaN layers grown on freestanding n + -GaN substrates with low dislocation density. The ICP etching caused slight disorder of the chemical bonds at the GaN surface and monolayer-level interface roughness at the Al 2 O 3 /GaN interface, resulting in poor capacitance--voltage ($C$--$V$) characteristics due to high-density interface states including nitrogen-vacancy (V \text{N ) related levels. The postannealing process in N 2 at 400 °C drastically improved the $C$--$V$ characteristics, probably owing to the partial recovery of the V \text{N -related defects and the increased ordering of chemical bonds in the GaN surface region.
Bibliography:Schematic illustration of the ALD-Al 2 O 3 /n-GaN/n + -GaN structure with and without ICP etching of the GaN surface. (a) $C$--$V$ curves of GaN MOS structures. The solid line indicates a theoretical curve without assuming interface states. (b) Interface state density distributions of the ALD-Al 2 O 3 /n-GaN structures. TEM images of the ALD-Al 2 O 3 /n-GaN structures. XPS spectra of the GaN surfaces before and after ICP dry etching. For comparison, the Ga 3d intensities are adjusted to be equal for both samples, and the N 1s spectra are normalized by the Ga 3d peak intensity.
ISSN:0021-4922
1347-4065
DOI:10.1143/JJAP.51.060201