Thermal-mechanical modeling of single crystal AlN and GaN

Authors
Karvanirabori, Payman
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Other Contributors
Maniatty, Antoinette M.
Picu, Catalin R.
Samuel, Johnson
Dutta, Partha S.
Bondokov, Robert
Issue Date
2014-08
Keywords
Mechanical engineering
Degree
PhD
Terms of Use
This electronic version is a licensed copy owned by Rensselaer Polytechnic Institute, Troy, NY. Copyright of original work retained by author.
Full Citation
Abstract
In this work, thermal-mechanical models are being developed, based on underlying micromechanical behavior of III-nitride single crystals at growth temperatures, for use in process design. A crystal plasticity model that is capable of capturing the underlying mechanisms of dislocation motion, multiplication, and interactions in wurtzite structure (hexagonal) crystals is defined to accurately model the elastic-plastic behavior of GaN and AlN crystals at elevated temperatures. The model for AlN is extended from relations developed for GaN based on available experimental data. Algorithms for integrating the constitutive model and computing the consistent tangent modulus are formulated, and the material model is implemented into a crystal plasticity finite element framework. Finite element models of crystal growth for different processing conditions are simulated. The simulation predicts cracking and dislocation defect density in order to improve the yield and reduce the manufacturing cost of high quality III-nitride semiconductors. Furthermore, the resulting simulation capability can be used in conjunction with relevant experiments to backout key thermal-mechanical material properties at high temperatures.
Description
August 2014
School of Engineering
Department
Dept. of Mechanical, Aerospace, and Nuclear Engineering
Publisher
Rensselaer Polytechnic Institute, Troy, NY
Relationships
Rensselaer Theses and Dissertations Online Collection
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