Effects of Interfacial Modification on Diamond Film Adhesion
Abstract
Microlithographic surface patterning has been investigated as a means of improving diamond film adhesion on noncompatible substrates. This technique produces significant improvements in film adhesion beyond identical unpatterned substrates, although sufficient film stresses can develop to induce subsurface substrate fracture. The substrate etching geometry can be chosen to simultaneously produce an antireflective surface relief. Polycrystalline diamond thin films offer a unique combination of physical properties highly desirable for optical device applications: high hardness, wideband transparency, chemical inertness, and high laser damage thresholds. Application of these coatings to optical device structures, however, is often impeded by poor film adherence and surface roughness. While films substantial thickness can be produced routinely on Si, films grown on numerous other optical materials under equivalent conditions often delaminate at thickness of only a few microns due to lack of interfacial chemical bonding, intrinsic growth stresses and thermal expansion mismatch. To fully exploit the potential of the diamond films in optical applications, fabrication on less-compatible substrates must be addressed. Additionally, the highly faceted polycrystalline diamond films cause high levels of scattering and normally must be polished to achieve good optical transmission.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1991
- Accession Number
- ADA237750
Entities
People
- A. B. Harker
- J. F. Denatale
- J. F. Flintoff