THIRD INTERIM REPORT FOR INTERIM THIN FILM INDUCTORS (Modification No.2)

摘要

This report describes a continuing program for fabricating miniature thin-film inductors. These inductors use flat spiral conducting paths on bulk ferrite substrates encapsulated with deposited ferrite film. The period covered is from 1 December 1963 to 1 March 1964.nFour tasks, all directed toward the problem of obtaining larger inductance values, have been pursued during this period. These are:n1. Study the effect of ferrite material thickness on the inductance of an encapsulated coil. It was determined that a 40-mil (1000 micron) thick layer of material is required for maximum permeability effect.n2. Fabricate spiral coils of increased air core inductance. The 1.8 micrometry 23-turn coil has not been completed because of evaporation mask alignment problems.n3. Fabricate spiral coils of a gold-rhodium alloy so that a ferrite film deposited encapsulating these coils can be annealed or sintered at elevated temperatures, i. e., greater than 1050C. The higher annealing temperature is required to obtain lower porosity and larger crystallites in the ferrite film for increased initial permeability. Some success in fabricating a coil that withstood 1100 C has been achieved.n4. Study techniques for fabricating two coils in a mutually aiding inductive geometry on a single substrate. The coils are separated by a ferrite film deposit. Absorption of the gold plating solution by the ferrite film has been a problem. This prevented the fabrication of a complete unit for evaluation.nConclusions are drawn from the results of these four tasks, and the program for the final quarter of this program is discussed.