Silicides from Ni/Co/Si Structure

摘要

The silicide layer used as a diffusion barrier in microelectronics is typically required to be below 500A thick, and the silicides also need to have low contact resistance at high processing temperatures. We fabricated 150A-Ni/150A-Co/p-Si(100) samples with a thermal evaporator, and annealed the samples for 40 seconds at temperatures ranging from 700 deg C to 1100 deg C using rapid thermal annealing. Sheet resistance of the annealed sample stack was measured with a four point probe. In addition, we investigated microstructural and compositional changes during annealing using transmission electron microscopy and auger electron spectroscopy. The sheet resistance measurements for our proposed Ni/Co composite silicide was below 5 OMEGA/Sq.. Moreover our newly proposed silicides were stable with the additional elevated annealing at 900 deg C for 30 min. Microstructures and Auger depth profiling showed that the silicides in our samples were consisted of Ni-rich and Co-rich ternary compound. Our result implies that Ni/Co composite silicide may have excellent high temperature stability which can be employed in sub-0.1 mu m CMOS process.