Accession Number : ADD005415

Title :   Zero Temperature Coefficient of Resistance Bi-Film Resistor.

Descriptive Note : Patent,


Personal Author(s) : Jones,William Kinzy

Report Date : 01 Aug 1978

Pagination or Media Count : 5

Abstract : A first thin-film resistor member, preferably TaN, is disposed over a second thin film member, such as NiCr, to completely cover the second member and act as a passivating layer preventing anodization of the second. The thin-film materials used for the first and second members have substantially an equal thin-film, sheet-resistance, resistance value per square (ohm), with the first material being trimmable for this purpose. Also, the TCR (temperature coefficient of expansion) of the first material is negative while that of the second is positive. These members are coupled in parallel with substantially equal lengths but with differing widths which permit the first to completely cover the second. The arrangement permits the TCR of the parallel circuit to be brought substantially to a zero value and, in any event, a value no greater than + or - 50 ppm/C. Additionally, the first member anodically protects the second with the protection being assured by the formation of an oxide film formed on the first by the trimming. The bi-film system is adapted for microcircuitry in that it provides an acceptable sheet resistance without requiring excessive lengths or widths of the parallel circuit members. (Author)

Descriptors :   *Patents, *Thin film resistors, Thin films, Tantalum compounds, Nitrides, Nickel alloys, Chromium alloys, Deposition, Substrates

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE