Reliability of Gold∕Stabilized Tantalum Metallizations for Microwave Power Transistors

Abstract

Thin film systems based on platinum‐tantalum‐gold and tungsten‐tantalum‐gold have been investigated as metallization contacts for microwave power transistors. Platinum and tungsten deposited between layers of tantalum effectively stabilized the tantalum against grain boundary diffusion. The present investigation shows that Pt‐Ta‐Au and W‐Ta‐Au metallizations (i) are metallurgically stable, (ii) resist electrochemical corrosion, and (iii) are readily processed with existing technology.