Ion Beam Analysis of Amorphous and Nanocrystalline Group III-V Nitride and ZnO Thin Films

Abstract

The ion beam analysis (IBA) techniques of Rutherford backscattering spectrometry (RBS), elastic recoil detection analysis (ERDA), nuclear reaction analysis (NRA), and particle-induced x-ray emission (PIXE) have been used to quantitatively determine composition, uniformity, impurity, and elemental depth profiles of major, minor, and trace elements of group III-V nitride and zinc oxide (ZnO) thin films prepared by various growth techniques. The IBA revealed that an amorphous GaN film prepared by ion beam assisted deposition (IBAD) has large variations in film thickness and composition coupled with typically 10–20% oxygen that was found to be essential to stabilize their amorphous structure. The IBA characterization of plasma-assisted molecular beam epitaxy (PAMBE) grown GaN, InN, and InCrN films revealed composition, impurity, and uniformity information of the films. The IBA of ZnO films prepared by radio frequency (RF) sputtering showed that the Zn/O ratio often varied significantly over the film thickness. Hydrogen was found to be a major impurity in the films with around one present in the as-deposited ZnO films. It is clearly shown that the nondestructive, quantitative, and rapid IBA measurements are very useful to develop and optimize growth protocols in respect to film thickness, stoichiometry, and especially in regard to hydrogen and oxygen impurities for group III-V nitride and ZnO thin films prepared by various growth techniques.