This thesis presents the fabrication of transparent conductive Boron-Doped CVD diamond (BDD) thin film with the appropriate processing parameters. The BDD shows the transmittance in the visible wavelength and good electrical conductivity. The depositing rate of Diamond films yields 0.37 £gm per hour with Hydrogen, Argon, Methane and oxygen as gas sources, and B(OCH3)3 was used as the doping source. Microwave plasma chemical vapor deposition (MWCVD) was performed for the BDD deposition. Also, PECVD was applied to grow diamond-like Carbon (DLC) film on silicon as substrate. Through systematical experiments, the influence of carrier gas flow rates of B(OCH3)3, the variation of ratio of Argon, and growth pressure of BDD on the transmittance in the visible light and electrical conductivity has been studied. In addition, dc bias was applied to synthesize diamond films and extend long depositing time shows the stable growth rate of diamond films. The thickness of BDD films increases and acquired more than 60% optical transmittance. BDD samples were analyzed by Raman Spectroscopy for the diamond quality, N & K Analyzer for the film thickness and optical properties. Van Der Pauw I-V Measurement and Hall Measurement were analyzed p-type diamond films carrier mobility, carrier concentration, electrical resistivity. By increasing Argon and applying negative dc bias can improve the growth rate and transmittance of diamond films. And the quality of diamond films could be improved by the coating of DLC on Si substrates. This work has achieved fabricating a transparent conducting BDD successfully.

One of two project reports. Part A can be found at: http://hdl.handle.net/11375/17866 / <p> It was observed that the spontaneous carrier lifetimes of GaAlAs injection lasers, as measured by the time delay method, exhibit a strong dependence on the DC bias current flowing through the laser. As the DC bias current is increased, the measured lifetimes decrease, passing through a minimum at bias currents less than 0.1 mA, and then rise again to an intermediate value at high bias currents. It was also found that the impedance of these lasers to fast current pulses drops sharply at the same DC bias currents as the minimum measured lifetime mentioned above. Evidence is presented to suggest that both of these effects are due to an electrical resonance between the stray drive circuit inductance and the DC bias dependent capacitance of the laser's junction under forward bias. </p> <p> In addition, two methods of determining the spontaneous carrier lifetime by other than the time delay method are described. One method involves measurement of the vector impedance of lasers to sinusoidal drive currents at frequencies less than 100 MHz, as a function of DC bias. The second method is based upon the frequency dependence of the phase shift between a sinusoidal drive current and the resulting spontaneous light. </p> / Thesis / Master of Engineering (ME)

The core used to build power inductors and transformers are soft magnetic materials. When there is alternating external field, the magnetic moments rotate and consume energy, which is the core loss. The core loss depends on the AC flux frequency, amplitude, waveform, DC bias and temperature. These dependences are nonlinear and difficult to predict. How to measure, model and analyze the core loss is a challenge for decades. In this dissertation, two new core loss measurement methods are introduced first. These two methods use the reactive cancellation concept to reduce the sensitivity to phase discrepancy, which will destroy the accuracy in classic two-winding method for high frequency high quality factor sample measurements. By using the new measurement techniques the accuracy can be improved by several orders. The first is for sinusoidal waveforms, and the second is for non-sinusoidal wave. The new methods enable high frequency core loss characterization capability, which will help scientists and engineers on material research and inductor/transformer design. Measurement examples, considerations and error analysis are demonstrated and discussed in detail. With the measurement techniques, the core loss under rectangular AC voltage and DC bias current are investigated. A new core loss model named rectangular extension Steinmetz equation (RESE) is proposed based on the measurement results. The new model is shown to be more accurate than the existing core loss models. Several commercially available MnZn ferrites are characterized and modeled. Other than conventional MnZn ferrite materials, three commercial LTCC ferrite materials are characterized for integrated power supply applications. Based on characterized properties of these LTCCs, a group of new LTCC ferrites are fabricated and tested. The new LTCC is fabricated by laminating commercial LTCC tapes and co-firing. The new LTCC is demonstrated to have over 50% more inductance over the commercial LTCC materials. This work indicates that the power electronics engineers should work with material engineers to get the optimum material for a given application. In the last part, the core loss of the partially saturated lateral flux planar inductor is analyzed. The challenge of the analysis is the complexity of the distribution of bias field and flux density in a highly biased planar inductor. Each point in the core is working at different excitation and bias condition, and the core loss density is very non-uniform. The proposed method combines the characterization tested in previous chapters and the commercial finite element tool. Experiments verified that the calculation errors are within about 10%. In conclusion, the research in this dissertation proposed a complete solution to measure, model and analyze the high frequency core loss. This solution will not only facilitate fundamental research on physics understanding and material innovation, but also development of power electronics and RF applications. / Ph. D.

Previous studies have demonstrated the sensitivity of the amplitude of the microwave radiation-induced magnetoresistance oscillations to the microwave polarization. These studies have also shown that there exists a phase shift in the linear polarization angle dependence. But the physical origin of this phase shift is still unclear. Therefore, the first part of this dissertation analyzes the phase shift by averaging over other small contributions, when those contributions are smaller than experimental uncertainties. The analysis indicates nontrivial frequency dependence of the phase shift. The second part of the dissertation continues the study of the phase shift and the results suggest that the specimen exhibits only one preferred radiation orientation for different Hall-bar sections. The third part of the dissertation summarizes our study of the Hall and longitudinal resistance oscillations induced by microwave frequency and dc bias at low filling factors. Here, the phase of these resistance oscillations depends on the contact pair on the device, and the period of oscillations appears to be inversely proportional to radiation frequency.

This thesis deals with the utilization of new principles of characterization of gate capacitances for sigma-delta modulators. Sigma-delta modulators are the integral part of sigma-delta analog-to-digital converters. The proposed new method is characterized by high resolution and modest requirements for laboratory equipment. It allows characterizing capacitances whose values are within the range which is used in sigma-delta modulators. The thesis contains description of the new method, the analysis of measurement accuracy and experimental results.