Diamond is highly desirable as a conformal thin-film coating for three-dimensional (3D) devices due to its extreme hardness, durability and biocompatibility, especially in the case of implantable medical devices and prosthetics. Recent advances in microwave plasma chemical vapour deposition (CVD) have enabled conformal coating of such 3D structures with nanodiamond films. However, these techniques have not been extended to micro-crystalline diamond, due to interactions between the 3D substrates and resonant microwave cavity. Here we demonstrate more uniform growth of CVD polycrystalline diamond (PCD) coatings on complex-shaped structures, with the use of in-cavity Faraday cages, to isolate the 3D sample from the microwave cavity. While this does disrupt the distribution of the microwave plasma, which surrounds the 3D structure, we show that growth of relatively uniform micro-crystalline and faceted PCD films is possible over the entirety of the exposed 3D sample surface. The resultant technique opens possibilities for the coating of complex 3D geometries with a wider range of diamond materials than has been possible to date.

金刚石由于其极高的硬度，耐用性和生物相容性，特别是在可植入医疗器械和假体的情况下，非常适合作为三维（3D）设备的保形薄膜涂层。微波等离子体化学气相沉积（CVD）方面的最新进展使得能够用纳米金刚石膜对此类3D结构进行保形涂层。但是，由于3D基板和微波谐振腔之间的相互作用，这些技术尚未扩展到微晶金刚石。在这里，我们演示了使用腔内法拉第笼将复杂形状的结构上的CVD多晶金刚石（PCD）涂层更均匀地生长，从而将3D样品与微波腔隔离开来。尽管这确实破坏了围绕3D结构的微波等离子体的分布，我们表明，相对均匀的微晶和多面PCD膜的生长在整个暴露的3D样品表面上都是可能的。最终的技术为使用复杂的3D几何形状涂覆比以往更大范围的金刚石材料开辟了可能性。