EVALUATION OF VAPOR DEPOSITION GROWTH OF OXIDE SINGLE CRYSTALS FROM METAL HALIDES
Abstract
A vapor phase growth technique was developed for the epitaxial growth of oriented ruby monocrystals. Crystals were grown up to 90.7 grams in 52 hours. Detailed investigations were made to determine the variables which influenced the formation kinetics of the reaction system represented by the following equation: (2-x)AlCl3(g) + xCrCl3(g) + 3H2(g) + 3CO2(g) reversibly yields CrxAl(2-x)O3(s) + 3CO(g) + 6HCl(g) where x >O and x = O for ruby and sapphire, respectively. These variables included substrate temperature, total pressure, orientation, reactant gas velocity and reactant gas partial pressures. Crystals were grown with total impurity levels as low as 4 ppm. Dislocation density decreased with increasing thickness of vapor overgrowth. Densities as low as 13/sq cm were measured on large vapor-grown alpha-Al2O3 platelets, although the vapor-grown monocrtstals generally exhibited a density reduction of one to three orders of magnitude over their flame fusion substrates.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1965
- Accession Number
- AD0616914
Entities
People
- Philip S. Schaffer