Investigation of Effect of Germanium on the Crystallization Process of Hafnium Aluminum Oxide Matrix

Abstract

Germanium (Ge) nanocrystals have been successfully synthesized in the hafnium aluminum oxide (HfAlO) matrix via co-sputtering and furnace annealing. The crystallization process of the HfAlO film has been studied using a combination of Raman spectroscopy, transmission electron microscopy, secondary ions mass spectrometry and X-Ray diffraction techniques. It was found that 800{degree sign}C is the ideal annealing temperature for synthesis of Ge nanocrystals in HfAlO matrix. A higher the annealing temperature will result in significant Ge outdiffusion and thus no formation of the nanocrystals. In addition, for the sample with relatively high Ge content (~23.3%) in the HfAlO matrix, a noteworthy Ge outdiffusion and the crystallization of the film were observed even upon the annealing at 800{degree sign}C. The crystallographic phase of the film was found to favor the orthorhombic phase.