skip to main content

SciTech ConnectSciTech Connect

Title: Atom probe tomography studies of Al₂O₃ gate dielectrics on GaN

Atom probe tomography was used to achieve three-dimensional characterization of in situ Al₂O₃/GaN structures grown by metal organic chemical vapor deposition (MOCVD). Al₂O₃ dielectrics grown at three different temperatures of 700, 900, and 1000 °C were analyzed and compared. A low temperature GaN cap layer grown atop Al₂O₃ enabled a high success rate in the atom probe experiments. The Al₂O₃/GaN interfaces were found to be intermixed with Ga, N, and O over the distance of a few nm. Impurity measurements data showed that the 1000 °C sample contains higher amounts of C (4 × 10¹⁹/cm³) and lower amounts of H (7 × 10¹⁹/cm³), whereas the 700 °C sample exhibits lower C impurities (<10¹⁷/cm³) and higher H incorporation (2.2 × 10²⁰/cm³). On comparing with Al₂O₃ grown by atomic layer deposition (ALD), it was found that the MOCVD Al₂O₃/GaN interface is comparatively abrupt. Scanning transmission electron microscopy data showed that the 900 °C and 1000 °C MOCVD films exhibit polycrystalline nature, while the ALD films were found to be amorphous.
Authors:
; ;  [1] ; ; ;  [2]
  1. Materials Department, University of California, Santa Barbara, California 93106 (United States)
  2. Electrical and Computer Engineering Department, University of California, Santa Barbara, California 93106 (United States)
Publication Date:
OSTI Identifier:
22305759
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 13; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM OXIDES; AMORPHOUS STATE; CHEMICAL VAPOR DEPOSITION; DIELECTRIC MATERIALS; FILMS; GALLIUM NITRIDES; IMPURITIES; INTERFACES; LAYERS; ORGANOMETALLIC COMPOUNDS; POLYCRYSTALS; TOMOGRAPHY; TRANSMISSION ELECTRON MICROSCOPY