A comparison of low-energy as ion implantation and impurity-free disordering induced defects in N-type gaas epitaxial layers

We have compared the electrical properties of n-type GaAs layers disordered by either 40 keV As ion implantation or an impurity-free process employing an SiO₂ capping layer. Current-voltage and capacitance-voltage measurements on Au Schottky barrier diodes fabricated on the processed layers showed that the impurity-free method retained the much better electrical quality of the GaAs epitaxial layers. Different sets of defects were observed in the implanted samples and impurity-free disordered samples, which meant that the charge transfer across the Schottky barriers was different in the two cases. Our results further reveal that the concentrations and diffusion lengths of defects created by ion implantation were much larger. The impurity-free method retains the better electrical quality of the semiconductor material.