Plasma etching of cavities into diamond anvils for experiments at high pressures and high temperatures

Abstract

We describe a method for precisely etching small cavities into the culets of diamond anvils for the purpose of providing thermal insulation for samples in experiments at high pressures and high temperatures. The cavities were fabricated using highly directional oxygen plasma to reactively etch into the diamond surface. The lateral extent of the etch was precisely controlled to micron accuracy by etching the diamond through a lithographically fabricated tungsten mask. The performance of the etched cavities in high-temperature experiments in which the samples were either laser heated or electrically heated is discussed.

Keywords:

• plasma etching
• high temperature
• laser heating
• lithography
• designer anvils

Acknowledgements

The authors thank I. Kantor and V.B. Prakapenka for their assistance with the laser-heating experiments at GSECARS, and thank P.K. Dera for use of the X-ray diffraction software package developed by him. This work was performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Portions of this work were performed at GeoSoilEnviroCARS (Sector 13), Advanced Photon Source (APS) at Argonne National Laboratory. GeoSoilEnviroCARS is supported by the National Science Foundation – Earth Sciences (EAR-0622171) and Department of Energy – Geosciences (DE-FG02-94ER14466). Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.