Surface morphology evolution of a polycrystalline diamond by inductively coupled plasma reactive ion etching (ICP-RIE)

Abstract

The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above. ; The needle-like surface morphology evolution in oxygen plasma in combination with a secondary gas (Cl2, CHF3 or CF4) by inductively coupled plasma reactive ion etching (ICP-RIE) on a free-standing polycrystalline diamond was investigated. The addition of CF4 can produce trans-polyacetylene (t-PA), which is similar to the result when the pure O2 etching takes place, and generate compact needle-tip particles. However, the t-PA disappears with the introduction of Cl or H ions. The optimised etching parameters for the needle-like structure formation are as following: Cl2/O2 ratio 20% and RF-power (RFP) 100 W, where more compact and even nano-needles are realised with an average etching rate of 2 μm/min. The Cl2/O2 plasma etching results indicate that the time-dependent etching mechanism of diamond nano-needles results from (1 1 1) crystal plane selective etching and preferential graphitisation at the twin-plane boundary and dislocation area. ; This work was supported by the National Key Research and Development Program of China (no. 2016YFE0133200) and the European Union's Horizon-2020 Research program (no. 734578). Special thanks to the national high-level university-sponsored graduate program of China Scholarship Council (CSC). ; Peer-reviewed ; Post-print