Effects of Substrate Bias on the Diamond Nanostructure by Reactive Ion Etching

Abstract

Dense and uniform diamond nanocone arrays on titanium substrate were constructed by using bias-assisted reactive ion etching (RIE) of diamond films in a microwave plasma chemical vapor deposition (MPCVD) system. A hydrogen/argon mixture was employed as work gas with ratio of 3/1. The formation of nanocone structure was generated the lengthways physical bombardment/sputtering by argon ions, and selective chemical reaction of graphite and disordered carbons by hydrogen atoms and ions. The structure, size, and density depended on the substrate bias. The surface morphology of diamond film and nanostructures were characterized by field emission scanning electron microscope (FESME), and the composition of diamond film and nanostructures were characterized by Raman spectra. The Stopping and Range of Trons in Matter (SRIM) software was used to simulate the bombardment effect of the diamond film on different Ar⁺ ion incident angles during the etching process. The experimental results showed substrate bias at −180 V and −210 V was beneficial to the formation of high density, small size and sharp nanocones, meanwhile larger bias contributed to the formation of large size nanocones. Besides, as-prepared nanocones still maintained significant diamond phase.

Keywords:

• Nanocone
• titanium
• reactive ion etching
• MPCVD
• substrate bias

Additional information

Funding

This study was financially supported by National Natural Science Foundation of China (51575269).