Effect of as Passivation on Vapor-Phase Epitaxial Growth of Ge on (211)Si as a Buffer Layer for CdTe Epitaxy
Abstract
We report an investigation of epitaxial germanium grown by chemical vapor deposition (CVD) on arsenic-terminated (211)Si, which is the preferred substrate in the USA for fabrication of night-vision devices based on mercury cadmium telluride (MCT) grown by molecular-beam epitaxy (MBE). The films were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), cross-sectional transmission electron microscopy (XTEM), and x-ray diffraction (XRD). Arsenic passivation was found to be effective in preventing cross-contamination of unwanted residual species present inside the reactor chamber and also in prolonging the evolution of layer-by-layer growth of Ge for significantly more monolayers than on nonpassivated Si. The two-dimensional (2D) to three-dimensional (3D) transition resulted in Ge islands, the density and morphology of which showed a clear distinction between passivated and nonpassivated (211)Si. Finally, thick Ge layers ( 250 nm) were grown at 525 C and 675 C with and without As passivation, where the layers grown with As passivation resulted in higher crystal quality and smooth surface morphology.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 07, 2011
- Accession Number
- ADA591293
Entities
People
- Ishwara Bhat
- Priyalal Wijewarnasuriya
- Saurabh Garg
- Shashidhar Shintri
- Sudhir Trivedi
- Sunil G. Rao
- W. Pałosz
- Wendy L. Sarney
Organizations
- United States Army Research Laboratory