Influence of diamond-etching conditions on the fabrication of diamond microneedles by a thermochemical reaction of Ni in an H₂ atmosphere

Abstract

We examined the influence of diamond-etching conditions on microneedles fabricated by a thermochemical reaction between a Ni film with pinholes and a diamond (100) wafer in an H₂ atmosphere. The diamond microneedles fabricated by varying the annealing temperatures and thickness of the Ni film coated on the diamond were characterized by scanning electron microscopy. Relatively uniform and long diamond microneedles, with diameters of about 1 µm and heights of about 20 µm, were obtained by annealing for 6 h at 850 °C. For Ni films thicker than 1 µm, microneedles with inverted conical shape were obtained, whereas those fabricated with thinner Ni films exhibited a conical shape.