Epitaxial diamond encapsulation of metal microprobes for high pressure experiments

Diamond anvils with diamond encapsulated thin-film microcircuits have been fabricated for ultrahigh pressure electrical conductivity experiments. The diamond films were homoepitaxially deposited onto the diamond anvil substra tes with microwave plasma chemical vapor deposition using a 2% methane in h ydrogen gas mixture and a diamond substrate temperature of 1300 degreesC. T he diamond embedded thin-film microprobes remain functional to megabar pres sures. We have applied this technology to the study of the pressure-induced metallization of KI under pressures up to 1.8 Mbar. This technology has th e potential of greatly advancing the pressure range of a number of existing high-pressure diagnostic techniques, and for expanding the capabilities of diamond anvil cells into new directions. (C) 2000 American Institute of Ph ysics. [S0003-6951(00)00347-8].