Multiple Phase-Formation in Ni-Ge System Monitored by SEM, AFM and PIXE Analytical Techniques

Abstract

We present evidence of multiple phase formation in the Ni-Ge system observed with the aid of the Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM) and Particle Induced X-ray Emission (PIXE) analytical techniques. Using a conventional optical mask, we prepare lateral diffusion couples of thick rectangular germanium islands on a nickel thin film. We observe at elevated temperatures a lateral diffusion of excess atoms from the Ge rich island to the surrounding Ni thin film; in a process which leaves a sequence of clearly discernible multiple phases whose interfaces are optically resolvable. We reveal finer detail in structure, texture and stoichiometry of the phases using AFM and SEM micrographs together with µ-RBS (Microprobe Rutherford Backscattering Spectrometry) and µ-PIXE elemental distribution maps. Our results confirm that when complemented with AFM, SEM, and micro-Rutherford backscattering spectrometry, lateral diffusion coupling technique is the most effective method to observe simultaneously multiple phases in a metallic-semiconducting binary system.