The effect of annealing high-resistivity gas-source molecular beam epitaxial material which had been grown in the presence of an electron cyclotron resonance generated He plasma was reported. Previous work had shown that InP, when grown using this technique, exhibited a behavior which was attributed to the presence of defects that were produced by plasma particles during growth. In order to understand better the nature of these defects, samples were annealed at temperatures ranging from 500 to 700C and were evaluated by performing variable-energy positron annihilation, transient ellipsometric surface photo-reflectance, sheet resistance, and n-i-n device resistivity measurements. It was found that, for all of the samples, the resistivity increased with annealing; as did the carrier lifetime which was deduced from the optical measurements. This suggested the presence of more than one type of defect in the material. Positron annihilation studies suggested that open-volume defects, present in as-grown material as single vacancies and vacancy clusters, became larger during annealing. The latter effect could be obscured in Be-doped samples at higher annealing temperatures.

H.Pinkney, D.A.Thompson, B.J.Robinson, P.Mascher, P.J.Simpson, U.Myler, J.U.Kang, M.Y.Frankel: Journal of Vacuum Science and Technology A, 1998, 16[2], 772-5