The interfacial reaction of Ni with Si, Si₀.₇₅Ge₀.₂₅, and Ge at 400°C has been investigated. A uniform epitaxial NiSi film was obtained at 400°C for Ni-Silicidation on Si using rapid thermal annealing method. Similarly, uniform film of NiGe was formed at 400°C for Ni reaction with Ge. Whereas using in situ annealing at 400°C, Ni₃Ge₂ and NiGe were observed. For the interfacial reaction of Ni with relaxed Si₀.₇₅Ge₀.₂₅ films rapid thermal annealed at 400°C, a mixed layer consisting of Ni₃(Si₁₋xGex)₂, Ni(Si₁₋yGey), and Si₁₋zGez (z>y>x) was formed; whereas only Ni₃(Si₁₋xGex)₂ and Ni(Si₁₋yGey>) were observed by in situ annealing. / Singapore-MIT Alliance (SMA)

In this study, the FBAR devices fabrication was used by back-etched type. The titanium (Ti) seeding layer and platinum (Pt) bottom electrode were deposited by DC sputtering system using a dual gun. To improve the platinum (Pt) adhesion, a seeding layer titanium (Ti) is used. The piezoelectric zinc oxide (ZnO) thin films were deposited by RF reactive magnetron sputtering. By increase the substrate temperature and annealing treatment in order to improve the ZnO thin films quality. The FBAR device was fabricated with different top electrode of Al, Mo and Pt that was compared different frequency response characteristic. When ZnO thin films are deposited on Pt/Ti/SiNx/Si substrate by RF reactive magnetron sputtering, due to the lattice mismatch between the Zno thin film and Pt electrode and rapid deposition rate, the ZnO films have high Zn interstitials and O vacancy, which introduce the stress in ZnO films. By thermal annealing treatment the stress could be relaxed and the defects in ZnO films could be suppressed. We used the ZnO films at the different annealing temperature to fabricated the FBAR device, and also discussed the resonant characteristics of the FBAR device with the stress in the ZnO films. Top electrode of Al is suitable for using as electrode materials for FBAR device. The Al top electrode revealed the best frequency response characteristic among the various top electrodes in this research. Postdeposition annealing at 400¢Jmakes ZnO films more suitable for high Q FBAR device, it makes ZnO films with stronger c-axis (002) orientation, denser structure, smoother surface and relieved stress. The resonant frequency, the effective electromechanical coupling coefficient ( k eff ) and the quality factor (Q) were about 2.21GHz, 2.88% and 2659, respectively.

Recently, many dielectric materials have been considered as future promising candidates for a thin dielectric in DRAM storage capacitors. Due to its properties of high dielectric constant (£`// = 170, £`¡æ = 89), high refractive index (~2.5) and high chemical stability. TiO2 is a promising candidate for fabricating thin dielectrics in dynamic random access memory (DRAM) storage capacitors and as gate dielectrics of metal-oxide-semiconductor field effect transistor (MOSFET) without the problem of conventional SiO2 thickness scaling down in ULSI processes because of its high dielectric constant. TiO2 thin films grown on p-type (100) Si substrate are investigated by a cold wall horizontal MOCVD system using Ti(i-OC3H7)4, N2O and O2 as precursors in the growth temperature range from 400¢J to 700¢J. The growth rate of using N2O as the oxidizer is quicker than the growth rate of using O2 as the oxidizer because N2O is the more efficient in producing free O atoms. XRD results indicate that the structures of TiO2 films are polycrystalline and the phase transformation temperature of TiO2 films from the anatase phase to the rutile phase is about 650¢J. Electrical properties are strongly influenced by the growth temperature. The electrical properties of as-grown TiO2 films can be improved by annealing treatment. The TiO2 films using O2 as the oxidizer at the growth temperature of 600¢J has the highest dielectric constant of 119.3 and the lowest leakage current density of 1.43¡Ñ10-6 A/cm2 at the applied electric field of 1 MV/cm after annealing for 20 minutes in O2. In order to obtain the better electrical properties of TiO2 films on Si substrate, we prepared TiO2 films by combination of MOCVD and LPD. The dielectric constant of post-annealed TiO2 films prepared by combination of MOCVD and LPD is 34.1. And the leakage current density of it is 3.7¡Ñ10-6 A/cm2 at the applied electric field of 1 MV/cm. It is lower than the films prepared in the same MOCVD-TiO2 growth condition (about 8.2¡Ñ10-6 A/cm2). It suggests that this growth method can reduce the leakage current density.

The goal of this paper is to study the mechanism that may lead to the change of physic properties by annealed amorphous AZO samples, that were grown by RF magnetron sputtering, by an excimer laser or a tube furnace or both. By using of the Taguchi Methods, which is in expected to be a fast and efficiency method, to search the best process parameters and to understand what mechanism stood behind the change of these parameters. We found that polycrystalline AZO films may be formed very easily when were grown at a temperature higher than 150K. Amorphous AZO films may grow successfully only at low growth temperature, ~77K. Annealing in tube furnace can alter the crystalline properties. Recrystalization starts at 325oC. Laser annealing will also recrystalize the amorphous AZO films with laser energy density higher than 160mj/cm2. Unfortunately, neither method provide enough improvement in the electric conductivity.

Thesis--Ph. D., University of Hong Kong, 1986.

As a wide band gap semiconductor, Zinc Oxide (ZnO) has recently attracted considerable attention due to its wide applicability. Transition metal (TM) doped ZnO is one of the most intensive research field in the last decade because of its possible application in spintronics devices. The Co-implanted ZnO has been considered as one of the most promising candidate in the field of diluted magnetic semiconductor (DMS). In this study, the magnetic and structural properties of Co-implanted ZnO single crystal were investigated. ZnO single crystals were implanted with 100 keV-Co ions at 300K with a fluence of 1014cm-2and subsequently annealed at 750oC and 900oC respectively. The samples were studied by secondary ion mass spectrometry, X-ray diffraction, photoluminescence, X-ray photoemission spectroscopy and vibrating sample magnetometer. The as-implanted sample seemed to be phase pure while the spinel secondary phase ZnCo2O4 was present in 750oC and 900oC samples showed trace ofCo3O4,Zn0.52Co2.48O4 and metallic Co cluster. All the samples exhibited ferromagnetism at room temperature in low field region, and the magnetic moment was found to decrease and increase after the heat treatment. In high field region, typical paramagnetism was the dominating magnetic property. More than one ferromagnetic mechanism is involved to explain the experimental results. / published_or_final_version / Physics / Master / Master of Philosophy

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Thesis (Ph. D.)--Florida State University, 2005. / Advisor: Dr. Hamid Garmestani, Florida State University, College of Engineering, Department of Mechanical Engineering Title and description from dissertation home page (viewed June 14, 2005). Document formatted into pages; contains xv, 115 pages. Includes bibliographical references.