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Defect Content Evaluation in Single-Crystal AlN Wafers

Published online by Cambridge University Press:  01 February 2011

Robert T Bondokov ,
Kenneth E Morgan ,
Raj Shetty ,
Wayne Liu ,
Glen A Slack ,
Mark Goorsky  and
Leo J Schowalter
Robert T Bondokov
Affiliation:
[email protected], Crystal IS, Inc., 70 Cohoes Av, Green Island, New York, 12183, United States, 518-271-7375
Kenneth E Morgan
Affiliation:
[email protected], Crystal IS, Inc.
Raj Shetty
Affiliation:
[email protected], Crystal IS, Inc.
Wayne Liu
Affiliation:
[email protected], Crystal IS, Inc.
Glen A Slack
Affiliation:
[email protected], Crystal IS, Inc.
Mark Goorsky
Affiliation:
[email protected], UCLA, Department of Materials Science and Engineering
Leo J Schowalter
Affiliation:
[email protected], Crystal IS, Inc.
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Abstract

Aluminum nitride (AlN) offers exceptional properties necessary to explore the development of large area substrates for nitride based electronics and photonics. Recent studies on AlN bulk growth using the sublimation-recondensation method developed at Crystal IS demonstrated high-quality crystals with low dislocation density and crystallographic uniformity. The diameter enlargement of these AlN boules is often associated with extensive defect generation. The goal of this study is to evaluate the origin and distribution of growth defects in AlN bulk crystals.

AlN crystals were grown using the sublimation-recondensation technique and then they were sliced into wafers. The defect evaluation in this study was performed using x-ray topography, differential image contrast and polarized-light optical microscopy, atomic force microscopy (AFM) and etch pit pattern delineation. Special attention was paid to crack development and propagation, grain boundary distribution, micro-scale inhomogenities as well as to the origin and density of dislocations. The major cause of growth defect appears to be non-linearity of both axial and radial temperature gradients. Growth optimization results in lower defect density and improved crystallinity of the AlN crystals.

Keywords

crystal growthdefectsdislocations
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 892 , 2005 , 0892-FF30-03
Copyright
Copyright © Materials Research Society 2006

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References

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