Passivation of thin film resistor on dielectric or semiconductor - by applying oxygen-impermeable coating, pref. silicon nitride

摘要

Passivation of thin film resistors deposited on a dielectric or weakly doped semiconductor substrate involves (a) depositing a resistance film of a first substance (I) on the substrate and (b) depositing a layer of passivating substance (II), which prevents the passage of oxygen, (II) being a cpd. of elements not present in (I). Pref. (I) is beta- Ta (Ia) and (II) is Si3N4 (IIa). The O-impermeable layer prevents eventual change in the resistance value to partial oxidn. unlike conventional passivating methods. (IIa) is pref. deposited by cathodic sputtering of Si and a N atoms., pref. before as well as after stage (a). The (Ia) and (IIa) layers are 100-1000 angstroms thick.