Physical characterization of high-k gate dielectric film systems processed by RTA and spike anneal

As complimentary metal oxide semiconductor (CMOS) devices continue to scale with the rapid performance pace of Moore's Law, gate dielectric materials with significantly higher dielectric constants (k=10-25) are being investigated as potential replacements for silicon dioxide, SiO₂ (k=3.9), and silicon oxynitride. This provides opportunities for introduction of a physically thicker film with lower leakage current and with capacitance equivalent to <1.0 nm SiO₂ (A.I. Kingon et al, 2001; International Technology Roadmap for Semiconductors, 1999; G.D. Wilk et al, 2001; D.G. Schlom and J.H. Haeni, 2002). Changes in the composition of candidate materials; atomic layer deposited (ALD) and metal-organic chemical vapor deposited (MOCVD), uncapped hafnium dioxide (HfO₂), zirconium dioxide (ZrO₂), and hafnium silicate (Hf_xSi_1-xO₂ (x∼0.5)) have been evaluated by several techniques including: Rutherford backscattering spectroscopy (RBS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), X-ray reflectivity (XRR), secondary ion mass spectroscopy (SIMS), scanning electron microscopy (SEM), tunneling atomic force microscopy (TUNA), and high angle annular dark field scanning transmission electron microscopy with electron energy loss spectroscopy (HAADF-STEM-EELS). Trends associated with interfacial oxide growth, phase segregation, crystallization, and defect generation during anneal have been observed, although the corresponding reaction mechanisms are not thoroughly understood (B.W. Busch et al, 2000; B.H. Lee et al, 2000; T.S. Jeon et al, 2001; Y-M. Sun et al, 2000).