Development and Evaluation of an Instrument for Rapid Electroreflectance of Semiconductor Materials
Abstract
The applications of electron beam electroreflectance (EBER) to Hg(1- x)Cd(x)Te (MCT) and other semiconductor systems are desired. Temperature dependences of the E1 optical gap of MCT are in agreement with the results of other researchers. For an epitaxial sample, alpha E (1)/alpha T of -(6.7 to 8.2) x .0001 eV/K has been obtained. This value is consistent with that determined by Berlouis. We find a larger thermal coefficient for epitaxial MCT on CdTe than for bulk MCT. We have also measured the E(1) Delta (1) band gap to be nearly o. 63 eV above the E1 transition energy. MCT is more sensitive to electron beam current intensity than other materials due to its relatively poor thermal conductivity. The lineshape observed at .001 A/sq.cm appears to be from thermoreflectance (TR), based upon calculations and detailed experimental studies. Therefore, EBER determinations of the temperature dependence of the E1 and E1+Delta (1) band gap energies demonstrate a large variance. We have collaborated with other researchers on EBER evaluation of MCT growth and dry- etch processes. We have extended EBER studies to other technologically important crystal systems related to MCT. We have found correlations between the EBER measurements of CdTe samples and surface preparation methods. In the case of GaAs and related compounds, our results have shown promise in the analysis of epitaxial films and heterostructures, which are briefly described. Keywords: Mercury cadmium tellurides; Cadmium tellurides; Gallium arsenides.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 1989
- Accession Number
- ADA211690
Entities
People
- Michael H. Herman