Hydrogen etching on the surface of GaN for producing patterned structures

• Published in: Journal of crystal growth Vol. 314; no. 1; pp. 9 - 12
• Main Authors: Yeh, Yen-Hsien, Chen, Kuei-Ming, Wu, Yin-Hao, Hsu, Ying-Chia, Lee, Wei-I.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2011; Elsevier
• Subjects: A1. Hydrogen etching; A1. Surface processes; A1. Surface structure; A3. Hydride vapor phase epitaxy; B1. Nitrides; B2. Semiconducting III–V materials; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crystal growth; Defects and impurities in crystals; microstructure; Density; Depth profiling; Dislocations; Etching; Exact sciences and technology; Gallium nitrides; Holes; Linear defects: dislocations, disclinations; Low pressure; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Mooring; Physics; Porous materials; granular materials; Specific materials; Structure of solids and liquids; crystallography; Vapor phase epitaxy; growth from vapor phase; A1. Hydrogen etching; A1. Surface processes; A3. Hydride vapor phase epitaxy; B1. Nitrides; B2. Semiconducting III–V materials; A1. Surface structure; Pressure effects; Porous materials; VPE; Etching; Hydrides; Gallium nitride; III-V compound; B2. Semiconducting III-V materials; Dislocations; High pressure; Surface structure; Etch pits; Morphology; Low pressure; III-V semiconductors
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2010.10.063

The morphology of GaN etched in hydrogen atmosphere is investigated. It is found that GaN surfaces have different profiles after being etched at different pressures. The profile resembles a surface that has been decorated with columns or mooring posts at high pressure and with deep cavities at low pressure. Etch pit density (EPD) experiment shows all dislocations have been etched to form cavities at low pressure, but not all the cavities result from etched dislocations. A model has been developed to explain the mechanism of H 2 etching. Patterned structure with a flat surface and porous inside has been produced by two-step etching which is designed according to the model.