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Title: Microwave integrated circuits : preparation of, and measurement techniques for, metal and dielectric films
Author: Butlin, Richard Stephen
ISNI:       0000 0001 3512 7990
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1973
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The work reported in this thesis is concerned with evaluating the properties of materials used for lumped element microwave circuits. The investigation included surface roughness measurements of commercially available alumina and glass substrates, measurement of the surface resistance of evaporated, electroplated and bulk conductors, and measurement of the dielectric properties of alumina and silicon dioxide films. Factorially designed experiments were used to study the effects of the processing parameters for electroplating and RF sputtering on the quality of the metal and dielectric films obtained. The surface resistance measurements were performed using a cylindrical H011 cavity. The design of the cavity allowed a calibration curve to be drawn such that measurement of the return loss at resonance alone allowed the sample surface resistance to be read directly from a graph with an accuracy of ±0.0013Ω. The simplicity of the method is a significant advance on former methods. The effects of various surface finishing processes on the surface resistance of bulk conductors of copper and brass have been studied together with an investigation of the effects of the electroplating parameters on the surface resistance of copper films deposited from two acid solutions. The surface resistance of the metal films formed from those solutions was found to be dependent upon the current density, stirring rate, temperature and chemical composition of the solution. Results are also given for gold, silver and copper films deposited from commercially available plating solutions. The effect of film thickness on the surface resistance of evaporated copper films was also studied, the results being in good agreement with the theoretical values. The investigation of dielectric film properties required the construction of an RF sputtering unit. This is described in detail. The dielectric film properties were measured using a co-axial cavity. The effects of three sputtering parameters on the quality of the films obtained were studied. The application of a longitudinal magnetic field during sputtering was found to be particularly beneficial. A new technique has also been developed for the deposition of films onto selected areas of a substrate without the need for etching. This work was performed with a fellow research student and is covered by a UK Patent application. This method was required for the fabrication of microwave planar capacitors where the substrate and the capacitor dielectric were made of the same material.
Supervisor: Not available Sponsor: Science Research Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TK Electrical engineering. Electronics Nuclear engineering