Self-encapsulation of single-texture COSi2 nanolayer by TaSi2

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, selfencapsulation 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 degrees 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 degrees 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 degrees C. The sheet resistance of the CoSi(2) formed at 1000 degrees C was measured similar to 10 mu Omega 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 degrees C. (c) 2007 Elsevier B.V. All rights reserved.