Contribution of H ion etching under different substrate bias to the orientation degree of diamond films

An etching process of hydrogen ions was performed during the initial growth stage of diamond films. The H⁺ ion etching was performed by applying a negative substrate bias during a microwave plasma chemical vapor deposition process, using only hydrogen as a reactant gas. The contribution of H⁺ etching under different substrate bias and for different etching time to the orientation degree of diamond films was investigated by scanning electron microscopy and atomic force microscopy. It was found that an additional H⁺ etching process had influence on the orientation degree of deposited (001)-oriented diamond films. To achieve a significant improvement of crystal orientation, the bias voltage and etching time should be adjusted concerning to the situation of diamond films.