Summary
Due to the absence of commercially available native substrates, Aluminum Gallium Nitride (AlGaN) deep ultraviolet light emitting diodes are fabricated on lattice mismatched electrically insulating sapphire substrate requiring laterally conducting device designs. Lateral conduction geometry leads to a pre-mature power saturation resulting from device self-heating. Moreover, sapphire is a poor heat conductor which further aggravates the thermal issue. To address the above mentioned limitations, a vertical conducting device fabrication approach has been developed. A laser lift-off technique has been utilized to separate III-nitride thin-films from the sapphire and transfer onto a carrier substrate with high thermal conductivity. In this study, we demonstrate for the first time laser-induced delamination of LED MQWs structures at the AlN/sapphire interface. The laser power was systematically optimized in order to achieve crack-free epilayers ablation. Detailed thermal analysis for laser semiconductor interactions have been performed using analytical and finite element analysis (FEA) method to understand thermal behavior during laser lift-off (LLO) processing. Finally, vertically conducting deep UV and visible LEDs were fabricated to study power saturation and light extraction. Both the power saturation and the light extraction significantly improve due to the vertical conduction device geometry.
Read More ↓Edition Statements
- Publication Date:2009
Thesis Information
- Degree:Ph.D.
- University:University of South Carolina
- Advisor/Supervisor:M. A. Khan
- Pages:87
Publication Statements
- Language:eng
- Publication Date:2009
Edition Identifiers
- proquest:304993663
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