Nano-sized crystalline bacterial cell surface layer (S-layer) proteins have the intrinsic property to reassemble into two-dimensional arrays with ordered pores of identical size onto solid supports [1], ideal as a template for nanoscale patterning. In this work, we demonstrated that, when combined with area selective atomic layer deposition (ALD), the reassembled S-layer proteins can be effective nanotemplates to pattern nano-sized dielectrics, thus enabling further downscaling of logic and memory devices. S-layer proteins were reassembled on Si wafer to form two-dimensional arrays with ordered pores of identical size from the solution containing non-assembled protein units and 10 mM CaCl₂. Atomic force microscopy (AFM) and transition electron microscopy (TEM) images showed that the protein unit size and the pore diameter are about 10 nm and 5 nm, respectively. Octadecyltricholorosilane (ODTS) was used to modify the more hydrophilic protein surface since ODTS has been demonstrated to be an effective monolayer resist on a hydrophilic SiO₂ surface toward ALD of HfO₂ due to the existing of long organic chain.[2] High-k oxides were only deposited in the pores built by the protein units by an area selective ALD method after the S-layer nano-template was modified by ODTS. The nanopatterns of high-k oxides on Si wafer were obtained after the S-layer was selectively removed. Attenuated total reflection-fourier transform infrared spectroscopy (ATR-FTIR), contact angle measurement, and x-ray photoelectron spectroscopy (XPS) were employed to analyze the reassembling, modification, and removing process of S-layer proteins. FTIR analysis of the reassembled S-layer proteins before and after ODTS treatment revealed NH (3297 cm^-1), CH₃ (2968 and 2866 cm^-1), CH₂ (2922 cm^-1), CO (1645 cm^-1), and CN (1525 cm^-1) from S-layer proteins, while the intensity of CH₂ increased after modified by ODTS and increased with increasing ODTS modification time, due to the 17 CH₂ groups in ODTS. The ODTS treated S-layer proteins surface became more hydrophobic, evident by a contact angle change from 59^o to 84^o for 2h and 101^o for 40h. After cleaning, the peaks of NH (3297 cm^-1), CH₃ (2968 and 2866 cm^-1), CH₂ (2922 cm^-1), CO (1645 cm^-1), and CN (1525 cm^-1) from S-layer proteins disappeared, confirming that S-layer proteins have been removed completely. The current-voltage (I-V) of oxide nanopatterns is characterized by a conductive AFM.

[1] U. B. Sleytr, P. Messner, D. Pum, and M. Sara, Angew. Chem. Int. Ed., 1034-1054, 38, 1999. [2] R. Chen, H. Kim, P. C. Mclntyre, and S. F. Bent, Appl. Phys. Lett., 4017-4019, 84, 2004.