Epitaxial Thin Films for Microelectronics

With magnetron DC-cosputtering Ni and Al were deposited on n-type Si(001) wafers. In a following rapid thermal annealing process (RTA), solid phase reactions lead to the formation of thin NiSi2-xAlx epitaxial films. X-ray diffraction (XRD), X-ray reflectometry (XRR), transmission electron microscopy (TEM), Rutherford backscattering (RBS) and Au- ger electron spectroscopy (AES) have been used for film characterization. It is shown that the lattice mismatch between film and silicon, which is -0.46 % at room temperature in the case of pure NiSi2/Si, decreases with increasing content of Al in the ternary films. Increasing content of Al reduces the film roughness and improves its thickness homogeneity. For a depo- sition rate of Ni:Al = 1: 0.2 and annealing at 900 °C closed homogeneous epitaxial films with atomic smooth surface are formed.