Towards the production of very low defect GaSb and InSb substrates: bulk crystal growth, defect analysis and scaling challenges

摘要

In this paper we describe the bulk crystal growth and characterization of low defect mono-crystalline InSb and GaSb substrates suitable for use in the epitaxial deposition of infrared detector structures. Results will be presented on the production of single crystal InSb and GaSb ingots grown by both standard and modified forms of the Czochralski (Cz) technique. Material quality has been assessed by a new method of fully automated defect recognition microscopy (DRM) that enables crystallographic defect structures (etch pits) to be mapped and presented in real time. X-Ray Diffraction (XRD) assessments have been used to derive information on the spatial uniformity of bulk quality and this shows that very high quality crystals have been grown. Consideration has also been given to the requirements for manufacture of ≥4" diameter ingots that will be necessary to support the fabrication of very large area, Sb-based detector structures. The scaling challenges associated with InSb and GaSb production will also be discussed.