Phase and texture of Er-germanide formed on Ge(001) through a solid-state reaction

Abstract

The phase and texture of of Er-germanide formed on Ge(001) through a solid-state reaction between Er thin films and Ge(001) via rapid thermal annealing (300- 600°C) were investigated. It was found that amorphous ErGe1.2 forms at 300°C, followed by the formation of AlB2 hexagonal ErGe1.5 at 400- 500°C and then orthorhombic ErGe1.8 at 600°C. X-ray diffraction pole figure measurement revealed that the ErGe1.5 films formed at 400- 500°C consist predominantly of epitaxial grains with an orientation relationship of ErGe1.5 (1 1- 00)[0001]Ge(001)[01 1-], although the presence of a considerable amount of epitaxial grains with an orientation relationship of ErGe1.5 (10 1- 2)[01 1- 0]Ge(001)[010] was also observed in the film formed at 400°C. The germanide film formed at 600°C was found to consist of randomly orientated orthorhombic ErGe1.8 grains. Among the three different germanide phases, ErGe1.5 showed minimum resistivity values as low as ∼19 μ cm. © 2006 The Electrochemical Society.