Etch recipe allows engineers and product developers to design diamond devices

Advanced Diamond Technologies (ADT) is making broadly available an etch recipe which enables engineers and product developers to reliably and affordably design micro devices and sensors out of diamond.

Based on research published in the November/December 2009 issue of the peer-reviewed Journal of Vacuum Science & Technology B (JVST B), the etch recipe is available for download from ADT’s website at http://www.thindiamond.com. Using standard processes available in most foundries, this dry etch recipe enables designers to develop cutting-edge diamond micro devices and sensors while eliminating the complexity traditionally associated with diamond.

“A whole generation of 2D and 3D diamond structures are now conceivable such as high performance RF MEMS devices and accelerometers”

“The process to make diamond available, accessible, and affordable is complete. We have published this recipe so diamond can be incorporated into process flows using the same equipment and materials used to process silicon. We’ve eliminated the risk—and mystery—of how to make diamond devices and we hope to stimulate the creativity and ingenuity of designers to make diamond devices without having them worry about processing steps,” said ADT’s president, Neil Kane.

The article, “Nanofabrication of Sharp Diamond Tips by E-beam Lithography and Inductively Coupled Plasma Reactive Ion Etching,” describes the etch recipe developed while creating sharp diamond tips for atomic force microscopy (AFM) probes. The dry etch recipe was optimized to achieve a maximum etch rate of 650 nm/min using ADT’s UNCD^® Wafers. Parameters to achieve slower etch rates are also outlined which are applicable for developing delicate nano-structures. Process steps for creating and patterning the hard mask, a 350 nm thick plasma-enhanced chemical vapor deposited SiO_x layer, are also detailed.

“We have customers using our UNCD Wafers to make diamond products as diverse as AFM probes, switches for phased-array radar, biosensors to detect E. coli in water, LED lighting, and boron-doped diamond electrodes for water purification. A simple, optimized etch recipe makes the adoption of diamond very straightforward,” says ADT’s chief technical officer Dr. John Carlisle. “A whole generation of 2D and 3D diamond structures are now conceivable such as high performance RF MEMS devices and accelerometers,” said ADT’s MEMS lead scientist and lead author of the JVST B article, Dr. Nicolaie Moldovan.

The development of an optimized dry etch capability is part of ADT’s ongoing research to advance its 2009 R&D100 Award winning NaDiaProbes^®, the world’s first all-diamond AFM probes, which are created using UNCD Wafers as a starting material. NaDiaProbes are not diamond-coated probes or pieces of diamond mounted on cantilevers; rather the entire cantilever and tip assembly is made of UNCD, a thin-film form of nanocrystalline diamond.

ADT gratefully acknowledges its continuing collaboration with Argonne National Laboratory (Argonne) which is a co-author of the JVST B article. NaDiaProbes were developed with a grant from the National Science Foundation’s SBIR/STTR program.