Reduction of copper oxide by formic acid in a narrow gap under various conditions

In this study, the reduction rate of a copper oxide film by formic acid gas was measured under various conditions using a vacuum chamber and ellipsometer. The results revealed that the reduction rate of the oxide film in a narrow gap on the copper plate surface covered by a glass plate was 1.2 times greater than that on the surface of an uncovered copper plate. In addition, the reduction rate determined for a mixture of formic acid gas with a partial pressure of 1000 Pa and N2 gas with a partial pressure of 19 000 Pa was approximately two times lower than that measured for pure formic acid gas supplied at a pressure of 1000 Pa. Meanwhile, increasing the partial pressure of formic acid increased the copper oxide reduction rate. Finally, the reduction rates calculated using a direct simulation Monte Carlo method were in good agreement with the experimental data.