CAFM Studies of Epitaxial Lateral Overgrowth GaN Films

This thesis uses the techniques of atomic force microscopy (AFM) and conductiveAFM (CAFM) to study defect sites on GaN films. In particular, these defect sites demonstrate current leakage under reverse-bias conditions that are detrimental to device fabrication. Two growth techniques that were used to improve this leakage behavior for samples in this study included: epitaxial lateral overgrowth (ELO) and nano-ELO using a Si3N4 film. Both techniques decrease defects such as threading dislocations by controlling the nucleation and growth behavior of the GaN films. The EL0 technique uses a patterned dielectric film to laterally grow micron-wide regions (referred to as 'wings') that minimize dislocation defects. Our CAFM studies indicate that ELO films have no detectable leakage sites in these wing regions; however, between these regions the films have typical leakage site densities seen for standard films on the order of 107cm-3. The nano-ELO technique utilizes a porous Si3N4 film to reduce defects over the entire film, and CAFM data indicate nearly a factor of ten reduction in leakage site densities. The nano-ELO technique is therefore optimal for an overall improvement in film quality, whereas the ELO technique is suitable for device fabrication in patterned regions with optimized film quality.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Physics

Year dc:date.available

2007

Author dc:creator

• Kasliwal, Vishal P.

Contributors dc:contributor

• Dr. Alison Baski

• threading dislocation
• semiconductor
• growth behavior
• leakage
• defect site
• gallium nitride
• Physical Sciences and Mathematics
• Physics

Statement dc:rights

• © The Author

Identifier

https://scholarscompass.vcu.edu/etd/1412

OAI identifier oai:identifier

oai:scholarscompass.vcu.edu:etd-2411