Abstract: A two-head probe apparatus measures sheet resistivities of the thin layer on a semiconductor wafer. On one side of the wafer, a first probe head makes contact for injecting current into the wafer and measuring the voltage difference between two surface points. On the other side of the wafer, a second probe head makes contact for monitoring the substrate potential at two probed points on the wafer substrate. The second probe is disposed below a platen supporting the wafer, and the probe electrodes are moved into spring biased contact with the wafer through apertures in the platen by a vacuum actuated piston. Circuitry coupled to the two probe heads computes leakage current and displays sheet resistivity.

Abstract: A microminiature electrical delay line utilizes an m-derived filter formed by depositing a film of permalloy or other high permeability metal on a quartz or other dielectric substrate, then depositing a layer of quartz or other dielectric over the permalloy film, after which a plurality of microminiature thin film inductance coils are deposited on the dielectric layer and joined together electrically in series, a top layer of quartz or other dielectric then is deposited over the interconnected coils and a strip of permalloy or other high permeability metal is deposited over the top dielectric layer to extend across the coils, a gap being provided in the strip of permalloy at the central axis of each coil.

Abstract: A cooking apparatus includes a vessel having a flue extending vertically therethrough. A gas heater is disposed beneath the flue. Food is boiled in water contained in the vessel. The bottom of the vessel is curved, and the flue is configured with a restriction in the lower portion thereof to provide even distribution of heat applied to the vessel.