Method of fabricating a diamond membrane

A method of fabricating a diamond membrane, the method comprising:

• providing a substrate and a support structure, the substrate comprising a diamond material and having a first surface, the substrate further comprising a sub-surface layer that is positioned below the first surface of the substrate and has a crystallographic structure that is different to that of the diamond material, the sub-surface layer of the substrate being positioned to divide the diamond material into first and second regions wherein the first region is positioned between the first surface of the substrate and the sub-surface layer of the substrate, the support structure also comprising a diamond material and being connected to, and covering a portion of, the first surface of the substrate, the diamond material of the support structure comprising apertures;
• coupling the diamond material of the support structure to the first surface of the substrate in a manner such that portions of the first surface of the substrate are exposed within the apertures of the diamond material of the support structure;
• growing further diamond material on the first surface of the substrate at locations within the apertures of the diamond material of the support structure or at locations around the support structure to fuse the support structure to the substrate;
• and
• selectively removing the second region of the diamond material from the substrate by etching away at least a portion of the sub-surface layer of the substrate whereby a diamond membrane is formed and the support structure is connected to, and supports, the formed diamond membrane.