Transmission Electron Microscopy Study of Defect Reduction in Two-Step Lateral Epitaxial Overgrown Nonplanar GaN Substrate Templates
Abstract
Transmission electron microscopy (TEM) is carried out to characterize the extended defect reduction in low-defect nonplanar GaN substrate templates grown by lateral epitaxial overgrowth (LEO). The LEO nonplanar GaN substrate template has a trapezoidal cross section with smooth (0 0 0 1) and f11 22g facets. We demonstrate here the dislocation distribution and behavior in both ordinary LEO and two-step LEO. Penetration of threading dislocations (TDs) beyond mask windows is observed in ordinary LEO substrates. In twostep LEO substrates, which utilize the tendency for TDs to bend 901 at certain plane interfaces, only a type dislocations with Burgers vector b 1 3h11 20i are generated in the upper part above the TD bending zone between two mask windows with a density of 8 107 cm 2, and there are almost no dislocations in the LEO wing region. This approach provides a promising path to produce lowdefect GaN substrate templates for high-performance buried heterostructure lasers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2005
- Accession Number
- ADA471288
Entities
People
- Dawei Ren
- Paul Daniel Dapkus
- Wei Zhou
Organizations
- University of Southern California