Self-encapsulation Of Single-texture Cosi_2 Nanolayer By Tasi_2

摘要

In this work, we have studied single-texture formation of CoSi_2 layer in heat-treated Co/Ta_(0.7)W_(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_(0.7)W_(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 ℃ 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 ℃. 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 ℃. The sheet resistance of the CoSi_2 formed at 1000 ℃ 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 ℃.