Double doped low etch pit density InP with reduced optical absorption

Abstract

Liquid encapsulated Czochralski growth of low etch pit density, low optical absorption InP single crystals has been achieved by double doping with sulfur (donor) and zinc (acceptor) impurities. The etch pit density is controlled by the total impurity content N A + N D while the free carrier concentration, which determines the optical absorption, is controlled by the difference N D − N A of the active sulfur and zinc concentrations. Crystals having etch pit densities as low as 100 cm -2 and optical absorption as low as 1 cm -1 at 1.3 μm are reported.