Published online by Cambridge University Press: 26 February 2011
We have developed a process to grow both undoped, semi-insulating (SI) and silicon-doped, semiconducting (SC) GaAs using a vertical Bridgman method. The technique combines advantages of both liquid encapsulated Czochralski (LEC) and horizontal Bridgman (HB) processes. SI ingots, grown in pBN boats, and SC ingots, grown in quartz boats, are passed through a relatively shallow temperature gradient. Properties of the resulting material are highly uniform across the surface of a wafer. Because of the small temperature gradient, dislocation densities are very low (typically under 4000/cm∩2).