Indium tin oxide (ITO) thin films were formed on glass substrates by sol-gel method. Coating sols were prepared using indium chloride tetrahydrate (InCl3&bull / 4H2O) and tin-chloride pentahydrate (SnCl4&bull / 5H2O) stabilized in organic solvents (acetylacetone and ethanol). First attempt was to synthesize ITO thin films using standard/unmodified coating sols. The effect of calcination treatment in air (300 &ndash / 600 &deg / C) and number of coating layer(s) (1, 4, 7 or 10) on optoelectronic properties (electrical conductivity and optical transparency), crystal structure and microstructure of ITO thin films were investigated. In addition, single-layer ITO thin films with optoelectronic properties comparable to multi-layered films were prepared by employing organically modified coating sols. Oxalic acid dihydrate (OAD) &ndash / a drying/microstructure control agent&ndash / addition to standard sol formulation was achieved. The rationale was to improve the optoelectronic properties of ITO films through enhancement in microstructure and chemical characteristics upon OAD addition. The effects of OAD content in the sol formulation and post-coating calcination treatment on electrical/optical properties of ITO films have been reported. Finally, the effects of post coating drying temperature (100 &ndash / 200 &deg / C) and time (10 &ndash / 60 min) on optoelectronic and microstructural properties of OAD-modified ITO thin films were discussed. Thin films have been characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD),x-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-Vis) spectroscopy, fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM) and four-point probe measurement techniques. It was shown that film formation efficiency, surface coverage and homogeneity were all enhanced with OAD addition. OAD modification also leads to a significant improvement in electrical conductivity without affecting the film thickness (45&plusmn / 3 nm). Highly transparent (98 % transmittance in visible region) ITO thin films with a sheet resistance as low as 3.8&plusmn / 0.4 k&Omega / /sqr have been obtained by employing coating sols with optimized OAD amount (0.75 M). The optimum post-coating drying temperature (100 &deg / C) and drying time (10 min) was also determined for 0.75 M OAD-modified ITO thin films.

The pyroelectric ceramic thin films and detectors based on PbTiO3 that exhibits a low dielectric constant and a high pyroelectric coefficient were fabricated by a sol-gel method in this thesis. The lanthanum (La) and calcium (Ca) were adopted as dopants. The PLT and PCT thin films were deposited on Pt/SiO2/Si substrates by spin coating. 1,3 propanediol was used as solvent to minimize the number of cycles of spin coating and drying processes to obtain the desired thickness of thin film. By changing the dopant content and the heating temperature, the effects of various processing parameters on the thin films growth are studied. The effects of various dopant contents on the response of pyroelectric detectors are also discussed. Experimental results reveal that the dopant contents will influence strongly on the characteristics of thin films such as microstructure, dielectricity, ferroelectricity and pyroelectricity. With the increase of dopant content, the grain size, the coercive field (Ec) and the remanent polarization (Pr) of thin films decrease. The relative dielectric constant (£`r) and the pyroelectric coefficient (g) of thin films increase with increasing the dopant content. In addition, the results also show that the PLT(10) and the PCT(25) thin films exhibit large figures of merit Fv for voltage responsivity (Rv) and Fm for specific detectivity (D*) at the heating temperature of 700¢J. In the pyroelectric properties of thin film detectors, Rv and D* increased with an increase of dopant content. However, Rv and D* decreased when La and Ca content exceeded 10 mol% and 25 mol%, respectively. The PLT(10) and the PCT(25) pyroelectric thin film detectors exist both the maximums of Rv and D*. The results are consistent with the evaluations of Fv and Fm of thin films.

Abstract Recently, the large magneto-resistance effects in epitaxial manganite thin films has interested in the doped manganite perovskite materials for magnetic random access memory (MRAM) and read-head application. The relation between the magneto-resistance and microstructure of the colossal magneto-resistance materials has been evaluated in this study. Different thickness of La0.67Ca0.33Mn03 (LCMO) thin films were grown on (001) MgO and (001) SrTi03 (STO) substrates at growth temperature 750 degree C with RF magnetron sputtering technique, respectively. These substrates provide two different lattice-mismatch conditions for the LCMO films (+9% for MgO and +1% for STO). The crystal structure of LCMO films were characterized with X-ray diffraction (XRD), the surface morphology of LCMO films were observed by scanning electron microscope (SEM), the interface of microstructure between LCMO films and substrate were studied by transmission electron microscope (TEM), the thickness and chemical composition of LCMO films were determined by Rutherford backscattering spectrometer (RBS), and finally the resistance and I-M transition temperature were evaluated at temperature range from 77K to 300K. The results show that the epitaxial LCMO films with a superlattice structure were obtained on STO substrate and polycrystal structure of LCMO films were on MgO substrate due to larger lattice mismatch.. The transition temperature of magneto-resistance of LCMO thin film is quite sensitive with film thickness. The transition temperature increases with film thickness increased. When the film with thickness excess of 2000A, the transition temperature is nearly same as that of LCMO bulk material.. The existed strain and the microstructure of LCMO films are two important factors related with magnetic resistance and electrical properties of LCMO films.

Growth Mechanism and Infrared Detection of High-temperature Superconducting and Colossal Magnetoresistance Films Department of Electrical Engineering, National Sun Yat-Sen University Meng-Tsong Hong* Ying-Chung Chen**, Hsiung Chou** -------------------------------------------------- Abstract---- The growth mechanism of YBa2Cu3O7-d (YBCO) films grown by RF sputtering has been investigated. When growing films by RF sputtering, the shape of the plasma and the degree of resputtering effect were varied by setting different relative positions of the heater to the gun. As the substrate was near the plasma, the negative oxygen ions resputtered part of the mobile atoms from the surface of film back into the plasma, which caused the composition distortion, delayed the merge of grains and left uncovered holes. Setting a longer relative distance, the resputtering effect was suppressed and the precipitates appeared on the surface of films resulting in a rough surface. At an optimum relative position between heater and gun, the function of resputtering produced a polishing effect on the surface of films. This polishing effect suppressed the growth of precipitates without slowing down the growth of grains, a smooth and precipitate-free YBCO film might obtain. We also found that the film with smooth and precipitate-free morphology exhibited suppressed superconductivity. The most direct way to enhance the photoresponse of a bolometer is by modifying the microbridge from a single straight bridge to a meander or change the thermal coupling configuration between bolometer and heat sink. In the study of high-temperature superconducting (HTSC) bolometers, it is found that the geometry and thermal coupling configuration play very important roles on the behavior of heat conduction, which alter the thermal conversion efficiency, DT/WD. Actually, DT/WD is a matter of the absorption of the AC thermal irradiation and the dissipation of both the irradiation and the DC joule heat generated by the bias current. The competition between the capability of heat dissipation and the thermal generation determined the magnitude of DT/WD. The La0.67Ca0.33MnO3-y (LCMO) thin films with epitaxial structure and smooth surface morphology have been deposited. A LCMO thin-film microbridge was fabricated into a microbridge by conventional photolithography and dry etching for optical detection. The measured photoresponse, DV, of this LCMO thin-film microbridge reveals that it is bolometric in nature. The photoresponse is linearly proportional to the bias current Ib and the power density of irradiation WD, which strongly suggests the applicability of an LCMO thin-film microbridge to a linear optical detector. The ratio of the photoresponse to the irradiated power density, DV/WD, is independent of the incident-light wavelength l from 0.633 to 3.5 mm. The dependence of the photoresponse on modulated frequency f, follows the DV µ f -0.21 relation. Under Ib = 100 mA and f = 5 Hz at an operating temperature Top = 223 K, the responsivity S and noise voltage Vn are 685 V/W and 20 nV¡ÑHz -0.5, respectively, for this LCMO thin-film microbridge. From the measured S and Vn, the noise equivalent power (NEP) and detectivity D* were be calculated to be 2.92´10-11 W¡ÑHz -0.5 and 2.76´109 cm¡ÑHz 0.5¡ÑW -1, respectively, for this LCMO thin-film microbridge. The experimental results from this LCMO thin-film microbridge show the practical applicability of this new detector system compared to other established detectors. *Student **Advisor

Abstract Recent progress in oxide perovskite thin-film technology has led to the discovery of a large negative magnetoresistance in doped manganate perovskite thin films. These films may have potentials for magnetic random access memory (MRAM) and magnetic sensors. Therefore, the research of magnetoresistance has been attracted a lot of attentions. The magnetoresistance is directly related to the microstructure. In an application point of view, the ulta-thin film may be more appropriate compares with those utilizing with thicker films. In this paper, we report the detail results of electrical property of La0.67Ca0.33MnO3 (LCMO) films related with their microstructure. The La0.67Ca0.33MnO3 (LCMO) films were deposited on (001) STO substrate with RF sputtering technique. The working pressure was maintained at 100m torr and the growth temperature was kept at 750¢J. After growth the films was annealed at 850¢J for 1 hour in a 500 torr O2 annealing environment. The growth time was 3mins.¡B6mins. and 12mins. respectively. The crystal structure of LCMO films were characterized with X-ray diffraction (XRD). The surface morphology of LCMO films were observed by scanning electron microscope (SEM) and the interface of microstructure between LCMO films and STO substrate were investigated by transmission electron microscope (TEM). Finally the M-I transition temperature were evaluated with 4-point probe at the temperature range from 300K down to 77K. The results show that the LCMO films were amorphous when the growth time was in 3 mins. The microstructure of the film gradually became poly-crystal and had a (001) prefer orientation after the growth time increasing to 6 mins. The grain size of the 12 mins growth film was at 40-50 nm scale. The Curie temperature and magnetoresistance change of these films were increased as the degree of crystallization of these films became better.

Abstract With the advent of new technology, various machine structures and elements appear delicate and diminutive so that the nanotribological studies are needed in the modern mechanical technological development. Thin film lubrication will be indispensable as the basis of key-technology in high-technological devices and ultra-precision machines. Therefore, the research of thin film lubrication in the nanometer order is very important. In this research uses a self-development optical elastohydrodynamic lubrication (EHL) tester to simulate the oil film characteristics in the contact region between steel ball and sapphire under the pure rolling condition. First, the variation of oil film thickness on the contact region is observed by using the optical interference principle. An inverse approach of EHL is employed to investigate the pressure distribution on the contact region of lubricant. Final, the oil thickness and pressure distribution are substituted into Reynolds equation to predict the pressure-viscosity index of lubricant. Results show that the oil film thickness increases with increasing rolling speed, and curvature radius of steel ball, but decreases with increasing load. Moreover, when the oil thickness of ester lubricant is less than 17nm, the film thickness is obviously deviated that predicted by the classical EHL theory, and the pressure-viscosity index increases from 0.8195 to 0.9093. This result indicates that the ratio of the adsorbent layer to the oil film increases and causes the increase of the lubricant viscosity.

As technologies continue advancing, semiconductor devices with dimensions in nanometers have entered all spheres of human life. This research deals with both the statistical aspect of reliability and some electrical aspect of reliability characterization. As an example of nano devices, TaO_x-based high k dielectric thin films are studied on the failure mode identification, accelerated life testing, lifetime projection, and failure rate estimation. Experiment and analysis on dielectric relaxation and transient current show that the relaxation current of high k dielectrics is distinctive to the trapping/detrapping current of SiO₂; high k films have a lower leakage current but a higher relaxation current than SiO₂. Based on the connection between polarization-relaxation and film integrity demonstrated in ramped voltage stress tests, a new method of breakdown detection is proposed. It monitors relaxation during the test, and uses the disappearing of relaxation current as the signal of a breakdown event. This research develops a Bayesian approach which is suitable to reliability estimation and prediction of current and future generations of nano devices. It combines the Weibull lifetime distribution with the empirical acceleration relationship, and put the model parameters into a hierarchical Bayesian structure. The value of the Bayesian approach lies in that it can fully utilize available information in modeling uncertainty and provide cogent prediction with limited resources in a reasonable period of time. Markov chain Monte Carlo simulation is used for posterior inference of the reliability projection and for sensitivity analysis over a variety of vague priors. Time-to-breakdown data collected in the accelerated life tests also are modeled with a bathtub failure rate curve. The decreasing failure rate is estimated with a non-parametric Bayesian approach, and the constant failure rate is estimated with a regular parametric Bayesian approach. This method can provide a fast and reliable estimation of failure rate for burn-in optimization when only a small sample of data is available.

Many applications in microelectromechanical systems such as smart living space sensing system, microchannel system on chip and biomedical sensing system usually require instantaneously compensating or controlling the temperature of chip to acquire more linear and accurate output signal. So it is necessary to develop a micro temperature sensor or micro-hot-plate which has highly thermal isolation and low power characteristics. This thesis aims to design and fabricate a low power micro-hot-plate and a high-sensitivity temperature sensor for portable applications. This dissertation utilized a high power E-beam evaporator to deposit the platinum thin film as the material of temperature sensing and heating. The Pt layer is patterned using the lift-off technique. In addition, the micro-hot-plate can be released from the silicon substrate as a floating thin-plate using TMAH-based anisotropic etching technology. The floating structure can improve the thermal isolation and reduce the power loss through the silicon substrate. In this study, the higher temperature sensitivity (1914 ppm/¢J) and optimized sensing linearity ( > 99.9 %) of the platinum-based temperature sensor is demonstrated. On the other hand, the heating power of the floating micro-hot-plate developed in this research is only 14 mW when it be heated to 300 ¢J and the power efficiency is very high (18.3 ¢J/mW).

In this thesis, we investigate the synthesis of CuAlO2 on sapphire (0001) substrate by rapid thermal annealing of an Al2O3/Cu2O/sapphire structure above 1000oC. We examine the effects of growth conditions on the structural, formation mechanism, and optical and electrical properties of CuAlO2 thin film. The film prepared at 1100 oC in air was with epitaxial structure as verified by X-ray diffraction methods. Gas ambient, temperature ramp rate and reaction temperature are crucial parameters for the formation of CuAlO2 film. We found that single-phase CuAlO2 thin films formed in air ambient by a rapid temperature ramp rate above 1000oC. A slow temperature ramp rate and a pure oxygen ambient might lead to the appearance of second phase such as CuAl2O4. Optical gap of our films were determined to be 3.75 eV. Optical transmittance depended on the temperature of thin film reaction. The best transmittance obtained was 60 % by annealing at 1100 oC in air. Photoluminescence and cathodoluminescence measurements showed that the two peaks obtained are around 3.4 eV and 1.8 eV corresponding to UV and red emission. As a result of CuAlO2 has an indirect gap about 1.8 eV. The electrical conductivity of the film related to the oxygen content was investigated by the annealing experiments in oxygen-deficient (vacuum) and oxygen-excess (air) ambient. The sheet resistance of CuAlO2 increases consistently with an increase in the duration of the vacuum annealing. Further annealing in air restores the sheet resistance to the original value. The highest conductivity obtained in this work was 0.57 S/cm. Metal contacts to CuAlO2 were also studied in this work. The current-voltage characteristics showed that Cu, Al, Ni or Au could form Ohmic contact to CuAlO2. The lowest contact resistance was using Al metal. However, when the contacts were post-annealed above 300oC, the contact resistance was increased.

The thesis is divided into two parts. One is about the preparation of discotic liquid crystals Acid-6. The other is about the growth of Acid-6 thin film by thermal evaporation on silicon oxide surfaces and modified silicon oxide surfaces such as self-assembled monolayer(SAM) in different temperature. The surface morphology and molecular orientation of the thin film were studied by Atomic Force Microscopy(AFM) , X-ray Diffraction (XRD) , and then they were applicated to organic thin film transistor and measured properties by Semiconductor Parameter Analyzer. In the second part of our research, our expectative characteristics was not observed in different temperature and substructure. In the other side, we guessed that because discotic liquid crystals Acid-6 is negative semiconductor materials, so it is susceptible to hydrosphere, thus we can¡¦t observe the electric characteristic of OTFT in the atmosphere. In addition, due to discotic liquid crystals Acid-6 have biggish moleculer weight, thus its viscosity was so big that cause the diameter of Acid-6 crystals to be too small. Therefore, it influenced the carrier mobility. Finally, from the aspect of procedure about fabrication of the devices we can discuss whether this parameter of this device can apply to OTFT.