A Two-Stage Monolithic IF Amplifier Utilizing a High Dielectric Constant Capacitor

A two-stage monolithic IF amplifier incorporating sputtered Ta/sub2/0₅ capacitor has been fabricated. The monolithic capacitor is based on a composite layer structure consisting of Au, Ta, Ta₂0₅, Ta and Au. This layered structure is sequentially deposited in a single sputtering run, which eliminates all possibility of particulate contamination. As a result a thin pinhole-free dielectric layer can be deposited over large areas, and 140 pF capacitors have been fabricated with excellent yields. The large unit area capacitance of 1500 pF/mm² available with the present process has the potential for reducing the size and cost of both microwave monolithic circuits and hybrid thin-film circuits.