Self-encapsulation of single-texture CoSi2 nanolayer by TaSi2

In this work, we have studied single-texture formation of CoSi2 layer in heat-treated Co/Ta0.7W0.3/Si(100) structure. Moreover, self-encapsulation process of the CoSi2 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 Ta0.7W0.3 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 N2(80%) + H2(20%) ambient in a temperature range from 400 to 1000 °C for 60 min. X-ray diffraction analysis showed that a single-texture CoSi2 layer with (100) orientation was formed in this structure in the temperature range of 800-1000 °C. The self-encapsulation process of the CoSi2 layer has been also investigated by X-ray photoelectron spectroscopy. It was found that the CoSi2 layer was encapsulated by a TaSi2 layer in the temperature range of 800-900 °C. The sheet resistance of the CoSi2 formed at 1000 °C was measured ∼ 10 μΩ cm. Atomic force microscopy images showed that surface roughness of the TaSi2 surface was around 15 nm. Agglomeration of the TaSi2 on the CoSi2 layer resulted in increasing the surface roughness, at 1000 °C.