Liquid phase epitaxy growth of InGaAs with rare-earth gettering: Characterization and deep level transient spectroscopy studies

The liquid phase epitaxial growth of high purity InGaAs layers lattice matched to InP has been studied using rare earth dysprosium (Dy) as an impurity getter. Using this getter, the electron concentration decreased from 1.2 × 10¹⁸ cm⁻³ to 1 × 10¹⁵ cm⁻³ while the mobility at 300K increased from 3920 to 10200 cm²/V-s. The epilayers were characterized by resistivity, Hall effect, electrochemical capacitance-voltage profiling, photoluminescence, secondary ion mass spectroscopy, double crystal x-ray diffractometry, and deep level transient spectroscopy (DLTS). Significant improvement was observed in both electrical and optical properties of the layers with an increasing amount of Dy in the melt. The amount of Dy was thus optimized (6 × 10⁻⁴ atomic fraction) for the highest purity layer. The major background impurity was identified as silicon. The gettering of both acceptors, as well as donors, by Dy was established and gettering of oxygen was confirmed for the first time through DLTS studies.