Selected Energy Epitaxial Deposition and Low Energy Electron Microscopy of AlN, GaN and SiC Thin Films.
Abstract
Epitaxial growth GaN films at reasonable rates and at grazing incidence and using conditions similar to those employed for growth in a low energy electron microscope (LEEM) have been achieved. Preliminary phtoluminescence studies showed near band edge luminescence accompanied by yellow luminescence at -2.2eV. In situ experiments in the LEEM at ASU to produce a clean GaN substrate surface for homoepitaxy were performed. Heating the substrate to 880 deg C produced a (lx1) structure with meandering steps on the surface. Cleaning the substrates using a N-atom flux produced different atomic structures depending on the N-atom flux and the substrate temperature. Low N-atom flux gave rise to a structure with clear steps while a higher N-atom flux produced a (3x3) surface with vanishing steps. Growth of GaN on the (3x3) surface produced faceted layers. Additional in situ cleaning research at NCSU of MOCVD- grown GaN/AlN/611-SiC substrates using NH3-seeded supersonic molecular beams was investigated. Surface carbon and oxygen concentrations of-1%, as evidenced by XPS, were achieved by heating at 7300C under a hyperthermal NH3 flux. Oxygen was removed primarily by thermal desorption. In contrast, carbon removal required heating under an NH flux Ex situ AFM reveals a smooth surface with parallel steps after NH3 beam cleaning. 3 Homoepitaxial growth of smooth, highly textured GaN films was accomplished at 7000C by employing a hyperthermal NH3 beam (0.61 eV) and an effusive Ga source.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1998
- Accession Number
- ADA345293
Entities
People
- E. Bauer
- E. Chen
- H. Henry Lamb
- I. S. Tsong
- Robert F Davis
Organizations
- North Carolina State University