Pb(ZrxTi1 − x)O3 (PZT) films have excellent ferroelectric, optical, piezoelectric, and pyroelectric properties. We prepared PZT thin films by the excimer laser ablation technique. A pulsed KrF excimer laser (Lambda Physik LPX305icc, pulse duration of 25 ns, λ = 248 nm, 850 mJ Max.) was used to ablate the bulk targets. We investigated the influence of bottom electrode materials on the characteristics of the PZT thin films prepared on Pt and YBCO underlayers. The X-ray diffraction (XRD) patterns showed that the PZT films prepared with a laser fluence of 2 Jcm−2 on YBCO/MgO(100) substrate at a wide temperature range of 550–680 °C have a perovskite (007) structure. At the same laser fluence, the PZT films prepared on Pt/MgO(100) substrate have a perovskite (00l) structure only at 650 °C . The polarization-electric field (P-E) characteristics and fatigue properties of PZT thin films were measured by the Sawyer-Tower circuit. The remnant polarization and coercive field have been found to be Pr=15 μC cm−2, 30 μC cm−2 and Ec=200 kV cm −11, 100kV cm for Au/PZT/Pt/MgO and Au/PZT/YBCO/MgO correspondingly. The remnant polarization of Au/PZT/YBCO/MgO thin film was reduced to one-half after about 108 cycles of switching.

Pb (Zr1-x, Tix) O3 (PZT) ferroelectric thin films were prepared using the excimer laser ablarion technique. Optical emission of the PZT plasma plume was studied to understand the quantitative relation between the PZT film quality and the ablation plume plasma state. We identified the spectral lines originated in Pb, Pb+, Zr, Zr+, Ti, Ti+, O, O+, PbO, ZrO and TiO. These spectral intensities and dynamics have remarkable dependence on ambient O2 pressure. The X-ray diffraction patterns showed that the PZT films propared on MgO (100) substrate at 600°C and with a laser fluence of 2J/cm2 have a perovskite-pyrochlore mixed structure. The condition of 13Pa oxygen pressure provided high quality perovskite films. The ferroelectric properties of the Au/PZT/Pt/MgO structure were studied. The PZT perovskite structure (00l) was obtained on Pt (200)/MgO (100) substrate at 650°C. Polarizationelectric field curve for a PZT films with 200nm thickness showed a remanent polarization of 20μC/cm2 and a dielectric constant of 500.

Vapor-phase reactions in plasma plume during preparation of YBa2Cu3O7-x superconducting thin film are investigated using optical emission spectroscopy. Argon/oxygen gas mixtures of various ratios are used as ambient to study the formation of diatomic oxides. Most of YO and some of BaO molecules are formed in the vapor, while CuO molecules are not formed in the vapor but only ejected from the target. To obtain high-quality oxide thin films, fluxes of the oxide molecules. atoms and ions reaching a substrate, which are dependent on laser energy density, argon mixture ratio and total pressure, should be controlled.

Plasma phase oxidation was investigated during preparation of Y-Ba-Cu-O (YBCO) superconducting and Pb-Zr-Ti-O (PZT) ferroelectric thin films using KrF pulsed laser deposition. The YBCO and PZT plasma plumes were produced at a laser fluence of 0.1 to 6 J/cm(2), a mixture ambient of oxygen and argon and a pressure range of 10(-6)-1 Torr. In the YBCO ablation, YO and BaO molecules are formed in the ablation plasma with different reactivities, while most of the CuO molecules are ejected from the target. In the PZT film preparation, TiO molecules are generated in the plasma phase. Plasma phase oxidation affects strongly the characteristics of oxide superconducting and ferroelectric thin films.

Rugged surface polycrystalline silicon (poly-Si) films deposited by low-pressure chemical vapor deposition have been studied and the films have been applied to a storage electrode for stacked dynamic random access memory capacitors. The surface morphology of the films was drastically affected by growth conditions and by the film thickness. However, the rugged surface poly-Si was characterized by the growth of grains that have 〈311〉 preferred orientation. The grains had grown on the amorphous Si surface just after deposition in the low-pressure chemical vapor deposition furnace. It was observed that the amorphous Si films deposited at the transition temperature between amorphous and polycrystalline Si have small crystalline particles in the films. We surmise that the nucleation sites of rugged surface poly-Si grains are small crystalline particles in amorphous Si near the surface, because the amorphous Si films deposited at high SiH4 pressure and low temperature (less than 540 °C) that have no crystalline particles in the film show no grain growth of rugged surface poly-Si. Stacked capacitors were fabricated using rugged surface poly-Si films and thin silicon nitride dielectric films. It was found that the thin poly-Si film electrode about 100 nm thick deposited at 570 °C shows 2.5 times more surface area than that of the conventional poly-Si film electrode. A rugged surface poly-Si electrode deposited under optimized growth conditions is promising for high density dynamic random access memory with stacked capacitor cells.

Pb(ZrxTi1−x)O3(PZT) thin films have excellent ferroelectric, optical, piezoelectric and pyroelectric properties. We prepared PZT thin films using the excimer laser ablation technique. A pulsed KrF excimer laser was used to ablate PZT bulk targets. We have studied optimum preparation conditions such as an oxygen pressure, a laser energy fluence and a substrate temperature. In this paper, we investigated the composition, crystallization and ferroelectric properties of the PZT films prepared under various deposition conditions. The X-ray diffraction (XRD) patterns showed that the PZT films prepared on MgO(100) substrates at 600°C and with a laser fluence of 2J/cm2 had a perovskite - pyrochlore mixed structure. The condition of 100 mTorr oxygen pressure provided high quality perovskite films. It is found that the stoichiometric composition of the deposited films is obtained in ambient oxygen of 100-400 mTorr. The ferroelectric properties of the Pt/PZT/Pt/MgO structure were studied. The capacitance-voltage characteristics and the corresponding hysteresis loop of the dielectric-electric field curve were discussed. We also studied optical emission of the PZT plasma plume to understand quantitative relation between the PZT film quality and the ablation plume plasma. We identified spectral lines originated in Pb, Pb+, Zr, Zr+, Ti, Ti+, PbO and TiO. These spectral intensities have remarkable dependence on the ambient O2 pressure.

Si/sub 3/N/sub 4/ film deposited by LPCVD with in situ HF vapor cleaning has been applied to dielectric film of stacked capacitor. The composition of the Si/sub 3/N/sub 4/ film deposited on poly-Si electrode becomes stoichiometric. The film shows low leakage current and high electrical reliability. But it brings a new problem. Si/sub 3/N/sub 4/ film deposited using in situ HF vapor cleaning shows selective deposition on poly-Si electrode. The edge of poly-Si electrode is not covered by Si/sub 3/N/sub 4/ film. This problem is avoidable by carpeting Si/sub 3/N/sub 4/ film under poly-Si electrode. This process realizes further improvement of stacked capacitor dielectric film reliability.<>