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In order to test a critical lateral dimension in two dimensional (2D) planar ferroelectric, epitaxial PbTiO3 discrete islands were fabricated by both lithography process and chemical solution deposition process with different lateral size. The evolution of 90° domain structures as a function of film thickness and lateral dimensions was characterized extensively by reciprocal space mapping using the Huber six-circle diffractometer of the synchrotron x-ray diffraction beam line at Pohang Light Source. This method is useful for considering a reciprocal lattice point that is tilted out of the growth plane and has many advantages for the investigation of imperfect heterostructures. As the pattern size decreases in micron scale, the substrate clamping effects is significantly reduced and thus the misfit strain in the films could be relaxed further. As the lateral size of patterns decreases to about 100 nm by e-beam lithography, the quite different domain structures were observed especially in the strain distribution as well as tilting of a-domains. The new type of a-domains appeared in the nanoscale PbTiO3 patterns in the center of the reciprocal space map of tilted PbTiO3 (100) that has been observed in the continuous films. These new a-domains are aligned along the substrate normal without the tilting angle required to maintain an a/c twin boundary relationship. Equilibrium domain structures in the PbTiO3 thin film islands are also analyzed by the finite element simulation and found to be consistent with the experimental observation. In the case of nano islands formed by chemical solution deposition, c-domain abundance increases as both size and thickness decrease identically, which implies that if the size can be reduced below a certain critical size there exists only single c-domain. Compared to the case of patterns with lateral dimension of 100 nm and thickness of 100 nm which has a tendency of reduced c-domain abundance due to the reduction of compressive strain, islands with thickness of 30 nm and 120 nm lateral size have larger c-domain abundance. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

3D trench PbZrxTi1-xO3 (PZT) capacitors for 256 Mbit 1T-1C FRAM devices were characterized by synchrotron X-ray micro-diffraction at Pohang Light Source. Three layes, Ir/PZT/Ir were deposited on SiO2 trench holes with different widths ranging from 180 nm to 810 nm and 400 nm in depth by ALD and MOCVD. Each hole is separated from neighboring holes by 200 nm. The cross sectional TEM analysis for the trenches revealed that the PZT layers were consisted of columnar grains at the trench entrance and changes to polycrystalline granular grains at the lower part of the trench. The transition from columnar to granular grains was dependent on the trench size. The smaller trenches were favorable to granular grain formation. High resolution synchrotron X-ray diffraction analysis was performed to determine the crystal structure of each region. The beam was focused to about 500 μm and the diffraction patterns were obtained from a single trench. Only the peaks corresponding to ferroelectric tetragonal phases are observed for the trenches larger than 670 nm, which consist of fully columnar grains. However, the trenches smaller than 670 nm showed the peaks corresponding the pyrochlore phases, which suggested that the granular grains are of pyrochlore phases and non-ferroelectric. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]