Tailored ceramic film growth at low temperature by reactive sputter deposition

Reactive sputter deposition of ceramic films with tailored structure is addressed in this article. We begin with a brief overview of reactive sputter deposition specifically related to oxide and nitride films, including techniques for in situ plasma diagnostics. We identify two flux components in the plasma that have a controlling influence on film structure and stoichiometry: (1) the flux bearing sputtered target species, which consists of atoms (M) or reacted molecules (MOx or MNx), and (2) the reactive gas flux-containing species in various states of activation. Nonelectronic plasma reactions in which one partner is an excited rare gas species are described, and their role in modifying the sputtered flux, as well as in creating activated reactive gas species, is discussed. We then illustrate the general concepts presented in the overview using four examples of technologically interesting materials grown by rf diode sputter deposition at temperature below 300 degrees C, including: (1) fifth period metal (Zr, Y, Nb) oxides, (2) zirconia-alumina and zirconia-yttria nanolaminates, (3) nanocrystalline aluminum nitride, and (4) vitreous sp(2) and sp(3)-bonded boron nitride. Together, these diverse examples form a complementary set that demonstrates the ability to tailor film properties once the chemical and energetic parameters of the deposition process are understood.