The Development and Commercial Demonstration of Reliable Highly Adherent Metalization of AIN

60318 The substitution of AlN for beryllia (in microelectronics, high-power microwave tubes, heat sinks, etc.), to eliminate the adverse environmental and health impacts of beryllia, is presently hampered by a lack of suitable techniques for metallizing the AlN. Non-oxide ceramics such as AlN present a significant challenge for traditional metallization approaches used for conventional oxides. State-of-the-art commercial metallizing techniques for non-oxide ceramics have poor adhesion, are often cracked at the interface, and are rough and unreliable. This project will examine metal ion implantation into the AlN substrate with a transition to a controlled microstructure metal coating as a low cost reliable process to apply highly adherent metal coatings to AlN when substituting for beryllia. Phase I demonstrated that pulsed ion beam processing can be used to implant metals into the AlN surface with a transition to a controlled microstructure. The ion beam implanted metallized coatings on AlN had adhesive strengths greater than 80 MPa, the limit of the tester, whereas commercial metallized AlN strengths were under 50 MPa. A thermal resistance test showed that the metallized AlN was at least 20% better than commercial metallized beryllia despite beryllia¿s higher thermal conductivity. Phase II will address low cost optimization and process development, leading to the commercial demonstration of several applications of beryllia substitution. Commercial Applications and Other Benefits as describe by the awardee: The first application is as a substitute for all beryllia. Other applications include diode mounts, heat sinks, microelectric packaging tubes, and circuit boards.