VCZ法によるGaAs単結晶の成長(<特集>バルク結晶の成長(II))

抄録

We have developed VCZ method for growing GaAs and InP single crystals with low-dislocation-density. In this report, we show the growth by the VCZ method and the characterization of 4"φ and 6"φ semi-insulating and 3"φ Si-doped GaAs single crystals. In the VCZ method, a GaAs crystal is pulled under an arsenic atmosphere sealed in an inner chamber. The surface of the crystal isn't decomposed over 1100℃, therefore the crystal can be grown under a low tempertaure gradient so that growing a crystal with low dislocation density can be achieved. Dislocation densities of 4"φ and 6"φsemi insulating VCZ crystals are one order of magnitude and one third lower than that of the 4"φ LEC crystal respectively. The VCZ crystal includes low residual stress which causes cracking of a wafer and generating slip-dislocations in a wafer during hest treatments. In our heat treatment of 4"φ LEC and 4"φ VCZ wafers at 480℃, slip-dislocations are generated only in the LEC wafer. We have also successfully grown 3"φ Si-doped GaAs single crystals with wide dislocation free region by the VCZ method.