MBE Growth and Transfer of HgCdTe Epitaxial Films from InSb Substrates
An investigation of the heteroepitaxial growth of HgCdTe films onto InSb(211)B substrates is reported. High-quality HgCdTe(211)B single-crystal films have been successfully deposited onto InSb(211)B substrates and have been characterized with x-ray diffraction rocking curve analysis, etch pit density analysis, and surface void defect mapping. X-ray rocking curve (422) reflection full-width at half-maximum of 60 arcsec has been obtained for 7-μm-thick x = 0.22 HgCdTe epitaxial films, and etch pit densities of 3 × 106 cm−2 to 3 × 107 cm−2 have been observed. A significant reduction in HgCdTe void defect densities to 100 cm−2 to 200 cm−2 has been observed on InSb, including a complete absence of large “void cluster” defects that are often observed for growth on CdZnTe. Wafer bow induced by the growth of HgCdTe on InSb is less than 1 μm for 2-inch-diameter substrates. Significant diffusion of In into HgCdTe is observed for HgCdTe/InSb wafers that are subjected to Hg anneals at 250°C to 300°C. A preliminary investigation of the transfer of HgCdTe films from InSb onto Si substrates has also been undertaken, using an adhesive wafer bonding approach evaluated with scanning acoustic microscopy. The infrared transmission characteristics of the bonding adhesive have been investigated with respect to postgrowth annealing procedures to establish the compatibility of the bonding approach with HgCdTe device processing and detector operation.
KeywordsHgCdTe InSb detectors photodiodes molecular-beam epitaxy (MBE) heteroepitaxy wafer bonding
Unable to display preview. Download preview PDF.
- 7.J.D. Benson, P.J. Smith, R.N. Jacobs, J.K. Markunas, M. Jaime-Vasquez, L.A. Almeida, M. Martinka, L.O. Bubulac, and U. Lee, J. Electron. Mater., to be published.Google Scholar