PbTiO3-covered ZnO nanorods were grown on Al2O3 by metalorganic chemical vapor deposition (MOCVD), and their crystalline orientation was investigated by x-ray diffraction (XRD). Structural analysis by scanning electron microscopy and XRD revealed that the hexagonal ZnO nanorods had -side facets. XRD analysis of PbTiO3 thin films on ZnO/Al2O3revealed that PbTiO3 was epitaxially grown on ZnO, showing 6 variants of crystallites with the c-axis tilted either 27o or 69o from the surface normal to the ZnO plane. Effective piezoelectric coefficients calculated for the 27o and 69o-crystallites using piezoresponse force microscopy confirm that deformation of nanorods and nanotubes contributed to the large electrically-induced strain along the radial direction.

We have demonstrated that scanning nonlinear dielectric microscopy (SNDM) exhibited high performance and high resolution in observing the dopant concentration profile of transistors. In this study, good quantitative agreement between the SNDM signals and dopant density values obtained by SIMS in standard Si samples, which dopant concentrations have been calibrated. We succeeded in visualizing high-resolution dopant profiles in n- and p-type MOSFET with 40 nm gate channels. It is considered that SNDM would be an effective method in measuring the quantitative two-dimensional dopant profiles of transistors. Finally, we have succeeded in detecting the dopant profiles of SRAM memory cell transistors.

Using a scanning nonlinear dielectric microscopy (SNDM), we observed two standard Si samples with epitaxial staircase structures, which have known dopant density values calibrated by using secondary ion mass spectroscopy (SIMS). As the result, good quantitative correlation between dopant density values and SNDM signals was obtained without the phenomenon of contrast reversal effect, which is associated with conventional scanning capacitance microscopy (SCM) measurements. Thus, it is expected that SNDM will be an effective method for observing the quantitative measurement of two-dimensional dopant profiling on semiconductor devices.

We report on microstructure and ferroelectric properties of ultrathin PbTiO3 films epitaxially grown on SrTiO3(100), La-doped SrTiO3(100) and SrRuO3/SrTiO3(100) by MOCVD. High angle annular dark field scanning transmission electron microscopy, atomic force microscopy, x-ray diffraction and x-ray reflectivity measurements demonstrated that 1-20 monolayer (ML)-thick epitaxial PbTiO3 films had high-crystallinity, atomically flat surface and sharp interface at an atomic scale. The epitaxial relationship and thickness were also confirmed by these methods. Kelvin force probe microscopy and contact resonance piezoresponse force microscopy revealed that a 7ML (2.7nm)-thick PbTiO3 film grown on SrRuO3/SrTiO3 had the ferroelectric polarization.

To develop higher density FRAM requires reducing cell size. Therefore, the size effects resulting from device processing and the material's physical properties must be measured. Therefore, analyzing the electric characteristics of a single bit cell capacitor has become important. Two known characteristics of ferroelectric material are that the Vc increases at low temperatures, and the Pr falls at high temperatures. To further evaluate the impact of temperature on ferroelectrics, we constructed a new evaluation system based on a scanning probe microscope, that can measure the electric characteristics of a single bit cell capacitor. This system can be used in the temperature range from −120 degrees to 300 degrees C. We accomplished this by circulating liquid nitrogen around a SPM stage and by using an electrical heater. We measured the electrical properties of ferroelectric microcapacitors by using a sample with IrOx/PZT/Pt structure. Our measurements revealed that 2Pr really increases at low temperatures, and Pr decreases at high temperatures. That is, we have shown that Vc increases 30% at low temperatures and Pr decreases 10% also in an actual FRAM single bit cell capacitor.

We used scanning nonlinear dielectric microscopy to observe the position of electrons and holes in the gate SiO2-Si3N4-SiO2 (ONO) film of metal-oxide-nitride-oxide semiconductor type Flash memory. The electrons were detected in the Si3N4 part of the ONO film. The holes, on the other hand, were found in the Si3N4 film as well as in the bottom SiO2 film.

We examined the Raman spectra of the tetragonal Pb(Zr, Ti)O3 (PZT) films between FeRAM cells with a micro-Raman apparatus. We found that a Raman light peaked at 600cm−1 polarized linearly perpendicular to the polarization of the exciting light had a different intensity for each of the film.

We showed that the difference in the intensities can be explained by the differing distributions of grain orientations in the films. Based on this knowledge, we estimated the volume fraction of 90° domains as well as the average spontaneous polarization of the grains.