Characterization of Dislocations in HgCdTe Heteroepitaxial Layers Using a New Substrate Removal Technique

• Published in: Journal of electronic materials Vol. 38; no. 8; pp. 1746 - 1754
• Main Authors: Lamarre, P., Fulk, C., D’Orsogna, D., Bellotti, E., Smith, F., LoVecchio, P., Reine, M. B., Parodos, T., Marciniec, J., Tobin, S. P., Markunas, J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Boston Springer US 01.08.2009; Springer; Springer Nature B.V
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Electronics; Electronics and Microelectronics; Exact sciences and technology; Instrumentation; Linear defects: dislocations, disclinations; Liquid phase epitaxy; deposition from liquid phases (melts, solutions, and surface layers on liquids); Materials Science; Mercury cadmium telluride epitaxy; Methods of deposition of films and coatings; film growth and epitaxy; Optical and Electronic Materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optoelectronic devices; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductor research; Solid State Physics; Structure of solids and liquids; crystallography; Transmission electron microscopy; HgCdTe; transmission electron microscopy; dislocations; defects; LPE; Misfit dislocations; Dislocation glide; Etching; Burgers vector; Defects; Thin films; Sample preparation; Etch pits; Optical properties; Cadmium tellurides; Molecular beam epitaxy; Stress effects; Mercury tellurides; Passivation; Crystal structure; Infrared detectors; Epitaxial layers; Electrical properties; Photodetectors; Slip planes; Monocrystals; Transmission electron microscopy; Threading dislocation; II-VI semiconductors; Heteroepitaxy; Ohmic contacts; Arrays
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-009-0771-x

Dislocations are known to influence the electrical and optical properties of long-wavelength infrared (LWIR) HgCdTe detectors and have been shown to limit the performance of arrays fabricated on heteroepitaxial substrates. To help better understand dislocations in HgCdTe, a new method for preparing HgCdTe diagnostic epitaxial single-crystal samples by chemically removing the supporting CdZnTe substrate has been developed. Using this new sample preparation technique, the behavior of misfit and threading dislocations in HgCdTe epitaxial layers has been investigated by using a defect etch to reveal the dislocations present in the thin HgCdTe films. In most cases etch pits on the surface of the film are spatially correlated with etch pits on the bottom of the HgCdTe film. The small displacements of the related etch pits were used to obtain crystallographic information concerning the paths followed by threading dislocations on allowed slip planes in the HgCdTe crystal. In addition, transmission electron microscopy (TEM) is used to obtain more specific information regarding the Burgers vector of the dislocation. While this new sample preparation technique is useful for studying dislocations in HgCdTe epitaxial layers, it can also be used to study stress from ohmic contacts and passivation layers. The technique can be used for both liquid-phase epitaxy (LPE)- and molecular-beam epitaxy (MBE)-grown HgCdTe on CdZnTe substrates.