The growth of CoSi 2 using a Co/Zr bilayer on different Si substrates

Abstract

The growth of CoSi 2 between Co/Zr bilayers on amorphous and on crystalline silicon substrates was investigated. The Zr and Co films were deposited with an electron-beam evaporation system, followed by rapid thermal annealing using temperatures between 500 and 800°C with 100°C increments. The phase identification was carried out by XRD, and chemical compositions of these elements were analyzed by AES. The surface and interface morphologies of Co/Zr bilayer films were investigated by cross-sectional TEM. CoSi 2 was formed epitaxially on the crystalline Si substrate while polycrystalline CoSi 2 was grown on the amorphous Si substrate. The formation temperature of Cosilicide on the amorphous Si substrate was lower than that on the crystalline Si. The interface of the CoSi 2 layer formed on the amorphous Si substrate exhibits better uniformity than the CoSi 2 formed on the crystalline substrate. The sheet resistance of CoSi 2 on crystalline Si was lower than that on amorphous Si at high temperatures (700, 800°C) while the latter exhibited lower sheet resistance at low temperatures.