Substrate using epitaxial Al_2O_3 film for hetero-epitaxial growth and device applications

我们提出了用外延的γ-Al_2O_3薄膜作为缓冲层，在Si衬底上外延PZT薄膜和外延Pt薄膜。用化学气相沉积（CVD）法在Si衬底上外延生长γ-Al_2O_3薄膜，并报道了其应用。γ-Al_2O_3与Pt之间的晶格失配小于MgO与Pt之间的晶格失配。这表明在γ-Al_2O_3上外延生长Pt膜是可能的。本文首次报道了用γ-Al_2O_3缓冲层在Si衬底上外延生长Pt膜和PZT膜。用射频溅射法在Si衬底上外延生长了Pt薄膜，并以γ-Al_2O_3为缓冲层。沉积温度对Pt薄膜的结晶度有很大的影响。XRD和RHEED分析表明，在γ-Al_2O_3/Si衬底上生长了Pt外延膜。在γ-Al_2O_3/Si基片上外延Pt，可以改善铁电薄膜取向性决定的器件性能。

We proposed the use of an epitaxial γ-Al_2O_3 film as a buffer layer to form epitaxial PZT thin file and, epitaxial Pt films on Si substrates. The epitaxial γ-Al_2O_3 films were grown on a Si substrate using chemical vapor deposition (CVD) and their applications have been reported γ-Al_2O_3 is spinel structure as is MgO. The lattice mismatch between γ-Al_2O_3 and Pt is smaller than that between MgO and Pt. This suggests a possibility of growing epitaxial Pt films on γ-Al_2O_3. We report the first successful formation of epitaxial Pt films and PZT film on Si substrates by using an epitaxial γ-Al_2O_3 buffer layer. Epitaxial Pt films were successfully RF sputtered on Si substrates using an epitaxial γ-Al_2O_3 buffer layer. The Crystallinity of the Pt films was strongly affected by deposition temperature. XRD and RHEED patterns indicated that an epitaxial Pt film was grown on the γ-Al_2O_3/Si substrate. Epitaxial Pt on γ-Al_2O_3/Si substrates could provide a possible way to improve the performance of a device whose properties depend on the orientation of a ferroelectric film.