Impurity effect on the growth of dislocation-free InP single crystals

Dislocation-free InP crystals were pulled in a 〈111〉 %In direction by using a liquid encapsulation technique. InP crystals were free from dislocations only when they were grown from a melt doped heavily with impurities. Zn was found to be the most effective impurity to reduce the grown-in dislocation. Dislocation density was drastically decreased when Zn concentration exceeded a value of 1018/cm3. Donor impurities, such as S and Te, were also effective in reducing the grown-in dislocation. A single-bond energy model for the impurity effect on reduction of dislocations is proposed. Zn and S were presumed to also be effective in making dislocation-free GaAs, in light of this model. These were confirmed by experiment.