Ion mixing of Al2O3 and Al films on SiO2

Abstract

The influence of ion implantation on the interfacial chemistry, morphology, and adhesion of Al and Al2 O3 films on SiO2 was examined. The specimens were implanted with varying doses of 131 Xe+ and 84 Kr+ at different substrate temperatures (2×1016 Xe cm−2 at 130 °C, 1×1017 Kr cm−2 at 70 °C, and 1×1017 Kr cm−2 at 350 °C). These implanted specimens were compared to Al/SiO2 and Al2 O3 /SiO2 specimens vacuum annealed at 600 and 1000 °C, respectively. Unlike thermal processing, ion implantation induced substantial interfacial mixing and adhesion enhancement in both the Al2 O3 /SiO2 and Al/SiO2 specimens. Interfacial mixing and adhesion enhancement increased with ion dose. The adhesion increases (3–25×) were attributed primarily to interfacial Si–O–Al bonding. Interfacial bonding (adhesion enhancement) was promoted most extensively by implants which produced glassy interfacial mixtures. Implants that induced crystallization, resulting in phase separation, produced less extensive interfacial bonding. The 131 Xe+ and 84 Kr+ implants resulted in bubble, void, dendrite, and crack formation. Characterization was performed using Auger electron spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy, and x-ray diffraction. Film adhesion was examined using a scratch test.