Sun Niefeng

Identification of Defects in Undoped Semi-insulating InP by Positron Lifetime

Positron lifetime measurements, carried out over the temperature range of 10-300 K, have been used to investigate defects in two undoped semi-insulating InP samples. The positron lifetime spectra were analysed by both PATFIT and MELT techniques. The results at room temperature reveal a positron lifetime of around 273 ps, which is associated with indium vacancies VIn or VIn-hydrogen complexes. The positron average lifetime is temperature dependent and decreases with increasing temperature at the beginning (≤80 K and ≤120 K), and then remains unchanged, which is attributed to the influence of negative vacancies and detrapping of the positron from those negative ions of Mg, Zn, Ag and Ca with ionization level (1-).

Uniformity of Iron-Doped Semi-Insulating InP Wafers

Abstract 50 ∼ 100 mm diameter iron-doped InP crystal was grown by in-situ phosphorous injection synthesis liquid encapsulated Czochraski (LEC) method. Samples were characterized by high speed photoluminescence (PI) mapping and Etch pit density (EPD) mapping method. The perfection of these samples were studied and compared. 100 mm diameter InP single crystals were successfully developed by rapid P-injection in-situ synthesis LEC method. The EPD across the ingot was less than 5 × 104 cm−2, which was almost equal to the crystals of diameter 50 and 76 mm. By adjusting the thermal field and ensuring the chemical stoichiometry, InP crystals of larger diameters and good performance could be developed.

Model of defect formation in annealed undoped and Fe-doped liquid encapsulated Czochralski InP

Infrared absorption spectroscopy measurements indicate high concentration of hydrogen indium vacancy complex V/sub In/H/sub 4/ in undoped and Fe-doped liquid encapsulated Czochralski (LEC) InP. Annealed undoped and Fe-doped semi-insulating (SI) InP are studied by room temperature Hall effect measurement and photocurrent spectroscopy. The results show that a mid gap donor defect and some shallow intrinsic defects are formed by high temperature annealing. This mid gap defect is shown to be phosphorus antisite related. Defect formation process and compensation mechanism in annealed SI InP are discussed.