Self-encapsulation of single-texture CoSi 2 nanolayer by TaSi 2

Abstract

In this work, we have studied single-texture formation of CoSi 2 layer in heat-treated Co/Ta 0.7W 0.3/Si(100) structure. Moreover, self-encapsulation process of the CoSi 2 layer and surface roughness of the encapsulated layer, as a contact layer, has been examined. A direct current magnetron co-sputtering technique was employed to deposit a 10 nm Ta 0.7W 0.3 alloy intermediate layer. After growth of the layer on the Si substrate, a 25 nm Co layer was deposited using thermal evaporation method. Post-annealing process of the films was treated in an N 2(80%) + H 2(20%) ambient in a temperature range from 400 to 1000 °C for 60 min. X-ray diffraction analysis showed that a single-texture CoSi 2 layer with (100) orientation was formed in this structure in the temperature range of 800–1000 °C. The self-encapsulation process of the CoSi 2 layer has been also investigated by X-ray photoelectron spectroscopy. It was found that the CoSi 2 layer was encapsulated by a TaSi 2 layer in the temperature range of 800–900 °C. The sheet resistance of the CoSi 2 formed at 1000 °C was measured ∼ 10 μΩ cm. Atomic force microscopy images showed that surface roughness of the TaSi 2 surface was around 15 nm. Agglomeration of the TaSi 2 on the CoSi 2 layer resulted in increasing the surface roughness, at 1000 °C.