Non-contact polishing of single crystal diamond by ion beam etching

Sichen Mi,Adrien Toros,Teodoro Graziosi,Niels Quack

doi:10.1016/j.diamond.2019.01.007

Sichen Mi, Adrien Toros + Show 2 more

Open Access

https://doi.org/10.1016/j.diamond.2019.01.007

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Abstract

We propose a non-contact surface finishing method for brittle substrates by ion beam etching and we experimentally demonstrate polishing of (100) single crystal diamond surface. We model and simulate the polishing process, and verify the results experimentally by monitoring individual defects during the surface treatment. Rapid flattening of scratches and digs, as typically present on brittle substrates after mechanical polishing, is observed: trench depth is typically removed by 95% in less than 30 min. The polishing method relies on physical bombardment of the substrate surface with accelerated inert gas ions, rendering it highly versatile and applicable to a wide variety of materials.

Highlights

Single crystal diamond (SCD) has for long drawn interest in fundamental and engineering research, owing to its outstanding material properties [1], such as the highest thermal conductivity and mechanical hardness of any known bulk material, ultra-wide optical transparency, as well as extraordinary resistance to various chemicals
Current technology in chemical vapour deposition (CVD) has led to the demonstration of high-quality synthetic SCD [4], and polished SCD plates of dozens of square millimeters in size and hundreds of microns in thickness have become commercially available [5,6], suggesting that SCD may serve as an ideal material platform for large-scale nanophotonics applications
We present a non-contact surface polishing method using ion beam etching (IBE) with simultaneous sample rotation, which is fast and circumvents the difficulties associated with the surface preparation by traditional fine polishing methods, such as polishinginduced subsurface damages [9]

Summary

Introduction

Single crystal diamond (SCD) has for long drawn interest in fundamental and engineering research, owing to its outstanding material properties [1], such as the highest thermal conductivity and mechanical hardness of any known bulk material, ultra-wide optical transparency, as well as extraordinary resistance to various chemicals. Several non-contact polishing methods have been shown to be useful for smoothening the polishing lines without inducing further damages, including dressed-photon-phonon etching [13], reactive ion etching (RIE) with specific recipes [14,4], and ion beam etching (IBE) with incidence angle smaller than 45° [15, 16]. They are not suitable for removing deep scratches. We present a non-contact surface polishing method using IBE with simultaneous sample rotation, which is fast and circumvents the difficulties associated with the surface preparation by traditional fine polishing methods, such as polishinginduced subsurface damages [9]

As-received diamond substrate

Polishing mechanism

Modeling and simulation

Experiment results and discussion

Conclusions