Fabrication of c‐plane‐oriented hydroxyapatite film on amorphous SiO2 substrate

Abstract

AbstractWe investigated a fabrication technique of c‐plane‐oriented hydroxyapatite (HA) crystalline film on low‐cost amorphous SiO2 substrates to apply the orientation‐controlled HA crystal to disposal biochips. An experiment was conducted by the pulsed laser deposition method. We showed that a high‐quality HA crystalline film was grown using a fluorapatite (FA) buffer layer, which was self‐oriented on amorphous SiO2. A relationship between an FA‐film thickness and the HA quality was examined with an aim of minimizing a toxic risk of F to biomolecules, even if it was eluted from FA. It was found that the thickness of the FA film could be reduced to about 7.5 nm, at the same time, the crystallinity and smoothness of HA were also excellent. A crystal growth model of FA on the amorphous SiO2 was also studied. We considered that highly reactive F in a laser‐ablated plume substituted for O on the substrate surface, which became a migration trap, causing three‐dimensional island growth as FA crystal nuclei. This model consistently agreed with a series of experimental results.