Defects and the Formation of Impurity ‘Hot Spots’ in HgCdTe/CdZnTe
Autor: | Scott M. Johnson, R. N. Jacobs, Jeffrey M. Peterson, L. O. Bubulac, J. M. Arias, D. D. Lofgreen, J. W. Bangs, Andrew J. Stoltz, L. A. Almeida, M. Reddy, J. D. Benson, A. Wang |
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Rok vydání: | 2019 |
Předmět: |
010302 applied physics
Materials science Analytical chemistry Oxide Polishing 02 engineering and technology Substrate (electronics) 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials chemistry.chemical_compound chemistry Impurity Desorption 0103 physical sciences Materials Chemistry Wafer Electrical and Electronic Engineering 0210 nano-technology Deposition (law) Molecular beam epitaxy |
Zdroj: | Journal of Electronic Materials. 48:6194-6202 |
ISSN: | 1543-186X 0361-5235 |
DOI: | 10.1007/s11664-019-07408-y |
Popis: | The formation of impurity ‘hot spot’ macro-defects—localized high impurity level contaminates—is examined. The evolution of macro-defects through their critical stages: as-received CdZnTe substrate, molecular beam epitaxy (MBE) prep etch, Te/oxide desorption and stabilization at deposition temp in MBE chamber, thin (200 nm) HgCdTe deposition, and thick (> 4 μm) MBE HgCdTe deposition, is analyzed. As-received CdZnTe wafers have small and large agglomerations of residual SiO2 and Al2O3 polishing grit. Additionally, macro-defects composed of organic residue, Cd(Zn)Te particulates, and additional impurities are also observed. The MBE preparation etch does not significantly alter the types of defects found on the wafer. The Te/oxide desorption process adds a small number of defects due to colloidal graphite particles. HgCdTe deposition introduces MBE spit defects and Hg droplet residue. There is significant movement of polishing grit and organic macro-defects during the various processing steps. Energy dispersive X-ray spectroscopy (EDS) analysis of MBE spit defects shows they are Cd rich with some of the spit defects containing high concentrations of impurities. The vertical gradient in Te concentration associated with the overgrowth on a metal rich MBE spit defect acts as an impurity pipe for Cu to travel toward the surface to become a ‘hot spot’ defect. |
Databáze: | OpenAIRE |
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