Undoped or Fe-doped liquid encapsulated Czochralski material was studied by using Hall effect, current-voltage and infra-red absorption spectroscopic techniques. The results indicated that a native H vacancy-complex donor-defect existed in as-grown samples. By studying the infra-red data, it was found that the concentration of this donor defect in Fe-doped material was much higher than that in undoped material. This result was consistent with the observation that a much higher concentration than the apparent net donor concentration was needed in order to achieve semi-insulating properties. By studying current-voltage and infra-red results for Fe-doped wafers from various positions in an ingot, a high Fe2+ concentration was found to be related to the existence of H complexes. The concentration of this donor defect was high in wafers from the top of the ingot. A correspondingly higher Fe2+ concentration could be detected in these wafers. The results revealed an influence of complex defects upon the compensation and uniformity of Fe-doped semi-insulating InP.

Native Donors and Compensation in Fe-Doped Liquid Encapsulated Czochralski InP. Y.W.Zhao, Y.L.Luo, S.Fung, C.D.Beling, N.F.Sun, X.D.Chen, L.X.Cao, T.N.Sun, K.Bi, X.Wu: Journal of Applied Physics, 2001, 89[1], 86-90