Epitaxial growth of Ni films by radio frequency sputtering on GaAs(001) with a TiN buffer

Abstract

A study is made of the epitaxial growth structure of a Ni film 123 nm thick on the GaAs(001) pre-covered with a TiN film of 3 to 118 nm in thickness. First, the TiN buffer layer is prepared on the GaAs at a temperature from 100 to 700 °C by reactively rf sputtering Ti in N 2 gas flowing at a rate from 1 to 10 sccm. Then the Ni film is deposited on the fresh TiN film at a temperature between 200 and 500 °C by rf sputtering Ni in pure Ar gas. X-ray diffraction and transmission electron microscopy are used to analyze the crystal and compositional structure of the samples. In our experiments, the highly ordered epitaxial growth was obtained with the crystallographic relationship of Ni(001)[001] TiN(001)[001] GaAs(001)[001] by the TiN deposition at 500 °C in N 2 gas flowing at 1.0 sccm, followed by the Ni deposition at 300 °C, where the degree of the Ni film epitaxy depends on the TiN thickness. In conclusion, the highest ordered epitaxial Ni film is grown on the 13 nm thick TiN buffer.