LIQUID-PHASE EPITAXY GROWTH OF HIGH-PURITY INP USING RARE-EARTH DYSPROSIUM GETTERING

Epitaxial layers of InP were grown on semi-insulating InP substrates by liquid phase epitaxy. The introduction of small amounts (4 x 10(-4)-1 x 10(-3) atomic fraction) of the rare earth dysprosium in the melt resulted in a substantial increase in electron mobility and a reduction in the electron concentration. The mobility increased from 2040 cm2 V-1 s-1 (without dysprosium) to 4200 cm2 V-1 s-1 (with dysprosium) at 300 K and from 2480 cm2 V-1 s-1 to 19 250 cm2 V-1 s-1 at 83 K. The carrier concentration accordingly decreased from 2.3 x 10(17) to 4 x 10(15) cm-3 (300 K). The results of secondary-ion mass spectrometry and photoluminescence measurements indicate that reduction in the dominant impurity silicon by gettering is responsible for the improved properties.