Antimonide based infrared materials: Developments in InSb and GaSb substrate technologies

In this work we report on the crystal growth and surface characterization of antimonide substrate materials. The Czochralski technique has been used to grow single crystal InSb and GaSb ingots with typical etch pit densities of <;1E2 cm^-2 and <;2E3 cm^-2, respectively. X-Ray topographs (XRT) have enabled the high resolution mapping of the defect structure in GaSb substrates, demonstrating that ingots can be produced with large areas of zero dislocation density. Epitaxy-ready surfaces with very low levels of surface roughness and uniform oxide coverage have been demonstrated for 4” GaSb. We have shown that smaller diameter antimonide ingot and wafer production processes can be scaled to deliver high quality substrates in large diameter form.