Transport properties and defects in semi-insulating and Si-implanted InP

The transport properties and defect levels in Si-implanted semi-insulating and liquid phase epitaxial InP have been studied by Hall and photoconductivity measurements. Wide variations in the conductivity and Hall coefficient have been measured in semi-insulating InP:Fe and the results have been analyzed and interpreted by appropriate charge neutrality models. The energy position of the Fe and Cr acceptor levels have been determined to be 0.68 and 0.40 eV, respectively, below the conduction band minimum. The implantation studies indicate that the electrical properties of the layers are very sensitive to implant dose and energy, the type and thickness of encapsulant and the anneal temperature. High-resistivity or p-type conductivity was observed in layers implanted with 6.0 × 10¹¹ to 4.0 × 10¹² cm⁻² Si⁺. In general, better results were obtained with sputtered Si₃N₄ encapsulation. Varying amounts of Fe and Cr outdiffused to the active layer during annealing and a dominant defect, 0.56 eV below the conduction band, was observed in the photoconductivity spectra.