Formation process of apatite layer on titanium-coated silicon wafer surfaces

抄録

Apatite-coated silicon wafers are expected to be utilized for novel biosensors or implants. However, the mechanism and optimum conditions for the formation of an apatite layer on silicon wafer surfaces are unclear. Herein, we examined the effect of pretreating silicon wafers with titanium sputtering and weak alkali aqueous solutions before immersing them in a simulated body fluid (SBF). A week after immersion, silicon wafer surfaces coated with thin titanium layers were covered by hemispherical apatite particles that were produced in a heterogeneous nucleation reaction, whereas untreated silicon wafer surfaces were covered by spherical particles that were produced in a homogeneous reaction. Pretreatment of titanium-coated silicon wafers with 0.1 M NaOH aqueous solution assured heterogeneous apatite formation. Both titanium-coated and untreated silicon wafers were fully covered by the apatite layer after soaking in the SBF for 2–3 weeks. These findings show that pretreatment of silicon wafers with titanium sputtering and weak alkali aqueous solution is effective for obtaining apatite-coated silicon wafers.