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Title: Improved heteroepitaxial MBE GaN growth with a Ga metal buffer layer

Abstract

We demonstrate that the use of pure gallium (Ga) as a buffer layer results in improved crystal quality of GaN epilayers grown by plasma-assisted molecular beam epitaxy on c-plane sapphire. The resulting epilayers show electron Hall mobilities as high as 400 cm 2 /Vs at a background carrier concentration of 4 x 10 17 cm -3 , an outstanding value for an MBE-grown GaN layer on sapphire. Structural properties are also improved; the asymmetric (101) X-ray rocking curve width is drastically reduced with respect to that of the reference GaN epilayer grown on a low-temperature GaN buffer layer. Nitrided Ga metal layers were investigated for different Ga deposition time. These layers can be regarded as templates for the subsequent Ga main layer growth. It was found that there is an optimum Ga metal layer deposition time for improving the electron mobility in the epilayer. Heating of the Ga metal layer to the epilayer growth temperature under nitrogen plasma is found to be sufficient to produce highly oriented GaN crystals. However, nonuniform surface morphology and incomplete surface coverage were observed after nitridation of comparatively thick Ga metal layers. This is shown to be the reason for the decreasing electron mobility ofmore » the epilayers as the Ga metal layer thickness exceeds the optimum value.« less

Authors:
; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE Director, Office of Science. Office of Basic Energy Studies. Division of Materials Sciences (US)
OSTI Identifier:
789120
Report Number(s):
LBNL-45958
R&D Project: 513330; TRN: AH200137%%397
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Conference
Resource Relation:
Conference: 2000 Spring Meeting of the Materials Research Society, San Francisco, CA (US), 04/24/2000--04/28/2000; Other Information: PBD: 15 May 2000
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BUFFERS; DEPOSITION; ELECTRON MOBILITY; ELECTRONS; GALLIUM; HEATING; MOLECULAR BEAM EPITAXY; MORPHOLOGY; NITRIDATION; NITROGEN; SAPPHIRE; THICKNESS; GAN MBE SAPPHIRE BUFFER

Citation Formats

Kim, Yihwan, Subramanya, Sudhir G., Krueger, Joachim, Siegle, Henrik, Shapiro, Noad, Armitage, Robert, Feick, Henning, Weber, Eicke R., Kisielowski, Christian, Yang, Yi, and Cerrina, Franco. Improved heteroepitaxial MBE GaN growth with a Ga metal buffer layer. United States: N. p., 2000. Web.
Kim, Yihwan, Subramanya, Sudhir G., Krueger, Joachim, Siegle, Henrik, Shapiro, Noad, Armitage, Robert, Feick, Henning, Weber, Eicke R., Kisielowski, Christian, Yang, Yi, & Cerrina, Franco. Improved heteroepitaxial MBE GaN growth with a Ga metal buffer layer. United States.
Kim, Yihwan, Subramanya, Sudhir G., Krueger, Joachim, Siegle, Henrik, Shapiro, Noad, Armitage, Robert, Feick, Henning, Weber, Eicke R., Kisielowski, Christian, Yang, Yi, and Cerrina, Franco. Mon . "Improved heteroepitaxial MBE GaN growth with a Ga metal buffer layer". United States. https://www.osti.gov/servlets/purl/789120.
@article{osti_789120,
title = {Improved heteroepitaxial MBE GaN growth with a Ga metal buffer layer},
author = {Kim, Yihwan and Subramanya, Sudhir G. and Krueger, Joachim and Siegle, Henrik and Shapiro, Noad and Armitage, Robert and Feick, Henning and Weber, Eicke R. and Kisielowski, Christian and Yang, Yi and Cerrina, Franco},
abstractNote = {We demonstrate that the use of pure gallium (Ga) as a buffer layer results in improved crystal quality of GaN epilayers grown by plasma-assisted molecular beam epitaxy on c-plane sapphire. The resulting epilayers show electron Hall mobilities as high as 400 cm 2 /Vs at a background carrier concentration of 4 x 10 17 cm -3 , an outstanding value for an MBE-grown GaN layer on sapphire. Structural properties are also improved; the asymmetric (101) X-ray rocking curve width is drastically reduced with respect to that of the reference GaN epilayer grown on a low-temperature GaN buffer layer. Nitrided Ga metal layers were investigated for different Ga deposition time. These layers can be regarded as templates for the subsequent Ga main layer growth. It was found that there is an optimum Ga metal layer deposition time for improving the electron mobility in the epilayer. Heating of the Ga metal layer to the epilayer growth temperature under nitrogen plasma is found to be sufficient to produce highly oriented GaN crystals. However, nonuniform surface morphology and incomplete surface coverage were observed after nitridation of comparatively thick Ga metal layers. This is shown to be the reason for the decreasing electron mobility of the epilayers as the Ga metal layer thickness exceeds the optimum value.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {5}
}

Conference:
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