Abstract Thin film nickel temperature sensors having a temperature coefficient of resistance of above +0.2 percent/* C and a resistance above 0.35 ohms per square are formed by electron beam evaporation of a high purity nickel source at pressures below 8 X 10 6 torr and deposition of the evaporated nickel atop a dielectric substrate, e.g. a polyimide film, heated above 60* C. The nickel film preferably is deposited to a thickness between 250 A and 3,000 A and masking is employed to produce a desired configuration in the deposited nickel film. To stabilize the resistance of the deposited nickel film, a dielectric encapsulant such as alumina, silica, a polyimide or a fluorocarbon then is overlayed upon the film by conventional vacuum deposition or bonding techniques.
A method of forming a temperature sensor according to claim 1 wherein said substrate is a polyimide heated to a temperature between 150* C and 300* C and said nickel is evaporated in a vacuum less than 1 X 10 6 torr.
Claim 2
Dependent Claim
34 words
A method of forming a temperature sensor according to claim 2 wherein said source is deposited at a rate greater than 30 A per second to a thickness between 750 A and 1,500 A.
Claim 3
Dependent Claim
25 words
A method of forming a temperature sensor according to claim 1 further comprising the steps of: depositing a dielectric encapsulating layer atop said nickel film.
Claim 4
Dependent Claim
36 words
A method of forming a temperature sensor according to claim 4 further comprising the steps of selecting the material for said encapsulating layer from the group consisting of a metal oxide, a polyimide, and a fluoroethylene.