Fabrication of polycrystalline diamond on a flexible Parylene substrate

This paper reports a novel fabrication process of transferring polycrystalline diamond (PCD) from a 3-inch silicon wafer onto a flexible Parylene-C substrate. Combining Parylene-C with PCD can improve the mechanical flexibility while preserving the benefits of PCD (biocompatibility, chemical inertness, high thermal conductivity and feasibility of being selectively doped to be a semiconductor or insulator). This fabrication process breaks the barrier that PCD cannot grow on flexible polymeric substrate due to high temperature processes (500-900°C), which exceeds the melting point of most flexible polymers. As a demonstration of the technique, we transferred boron-doped polycrystalline diamond (BDD) on a Parylene-C substrate and assembled μLEDs on BDD for a potential application in optogenetics. Electrical and optical characteristics of a fabricated device were investigated and discussed in the paper.