Thinning and patterning of CVD diamond films by diffusional reaction

Abstract

Thinning of diamond films is often costly and time consuming because of their extreme hardness. In this paper substantial thinning of diamond films (by as much as about 100 μm) through simple diffusional reaction at 900°C with Mn or Fe is reported. The observed thinning effect is attributed to the diffusional transfer of carbon atoms from diamond to manganese or iron in contact, since these metals exhibit large solid solubility for carbon at the reaction temperature. Mn appears to react with diamond much faster than Fe does. Patterning of diamond films by selective area deposition of Mn films followed by reaction heat treatment and chemical etching is also described. These thinning techniques using metal powders, foils or deposited films may conveniently be used for removal of undesirable parts of the films such as rough growth facets on the top surface or the fine-grained bottom layer with inferior physical properties. These techniques also allow simultaneous thinning of a large number of diamond films.