Redox agent enhanced chemical mechanical polishing of thin film diamond

TL;DR

This study investigates how adding different redox agents to a polishing slurry affects the chemical mechanical polishing of diamond, revealing that certain agents can accelerate polishing without altering surface oxygen content.

Contribution

It is the first to systematically examine the effect of various redox agents on diamond polishing performance and surface chemistry.

Findings

Oxalic acid speeds up polishing rate.

Hydrogen peroxide has minimal impact due to volatility.

Redox agents do not significantly change surface oxygen levels.

Abstract

The chemical nature of the chemical mechanical polishing of diamond has been examined by adding various redox agents to the alkaline SF1 polishing slurry. Three oxidizing agents namely, hydrogen peroxide, potassium permanganate and ferric nitrate, and two reducing agents, oxalic acid and sodium thiosulfate, were added to the SF1 slurry. Oxalic acid produced the fastest polishing rate while hydrogen peroxide had very little effect on polishing, probably due to its volatile nature. X-ray photoelectron spectroscopy (XPS) reveals little difference in the surface oxygen content on the polished samples using various slurries. This suggests that the addition of redox agents do not increase the density of oxygen containing species on the surface but accelerates the process of attachment and removal of Si or O atoms within the slurry particles to the diamond surface.