Aluminum oxynitride coatings for oxidation resistance of epoxy films

Aluminum nitride (AlN) and aluminum oxynitride (AlNO) films were sputter deposited onto epoxy coated silicon substrates. The films were characterized by: electron microscopy; atomic force microscopy; θ-2θ X-ray diffractometry; and profilometry. The surface morphology of the films was a function of the feed gas oxygen content. Amorphous aluminum oxynitride films formed with oxygen flows of more than 0.5 sccm yielded smooth, continuous coatings over the epoxy. The oxynitride/epoxy/silicon structure was exposed in an electron cyclotron resonance low Earth orbit simulator, and showed 2–3 nm roughening up to the maximum fluence of 2.4×1022 atoms/cm2. This is equivalent to 94–940 days in low Earth orbit, depending on orbit height.