Analysis of Stoichiometry-Related Defects in Group III - Nitrides
Abstract
Stoichiometry-related effects in various group III-nitrides and some GaAs-based materials were investigated. An essential part of this study were low-frequency (LF) noise analyses. The new LF-noise system, acquired with an AFOSR DURIP grant (no. F49620-01-1-0285) was set up and calibrated. LF-noise spectroscopy was then applied to GOI-based MESFETs (noise caused by excess arsenic-related defects) and AlGaN/GaN HEMTs (channel noise related to an early 2D/3D growth transition for high Al-containing AlGaN layers rather than a dislocation-related strain relaxation process). Both device types were processed at UC Berkeley. Different nitride materials were evaluated for their potential for engineering non-stoichiometric epilayers (intentional manipulation of native defect population). In carbon-doped GaN a new insight into the nature of the ubiquitous yellow luminescence (YL) was gained. The strong Yb. was found to be caused by > a dopant-related effect and to be independent of the concentration of gallium vacancies. Furthermore, co-doping with silicon greatly increased the Yb. which gives further evidence for a donor-acceptor complex as origin of the YL. These studies provide a first proof that a second mechanism for YL exists in GaN that is independent of the presence of Ga vacancies. Consequently, the trapping-detrapping of carriers at deep defects causing noise in carbon doped GaN device structures is dominated by doping-related defects rather then any native defects. A vacancy-related defect was found in post-irradiated GaN, the investigation of vacancy incorporation upon various growth related conditions and its control requires further research.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 31, 2003
- Accession Number
- ADA427968
Entities
People
- Eicke R. Weber
Organizations
- University of California, Berkeley