A bulk nanomachining method for suspended nanobeam and other free-standing structures

This technology is a bulk nanomachining methodology for fabricating suspended sub-micron and nanoscale nanobeam photonic and mechanical elements. It is based on standard planar fabrication processes (i.e. optical or electron beam lithography and plasma etching), but is able to fabricate suspended nanobeam structures from a starting bulk material (i.e. a single-crystal or thick film). In essence, the bulk nanomachining methodology “carves out” suspended nanobeam elements from a given material. The process is fundamentally different from conventional surface nanomachining of free-standing structures in that there is no thin film heterolayer structure, and an isotropic wet chemical etch is not used to sacrificially remove any sub-surface layer. Instead, the proposed process makes exclusive use of anisotropic plasma etching to etch the bulk material from two slanting opposite angles. The result is a bulk nanomachining process which yields suspended, triangular cross-section nanobeam photonic elements. The key breakthrough of this process is the ability to create suspended structures from a single crystal diamond bulk material, for optical resonators and mechanical resonators. It can also be used to carve out other bulk materials.


A scalable nanomachining process to fabricate suspended, free-standing structures, from a bulk material of single-crystal diamond. Intended to fabricate a variety of photonic, mechanical and optomechanical elements, such as beams, waveguides, ring and disk resonators, membranes and high Q factor electromagnetic cavities.

Suspended structures are pervasive in a variety of photonic, mechanical, and opto-mechanical elements such as beams, waveguides, ring and disk resonators, membranes, and high quality factor (Q-factor) electromagnetic cavities. They are crucial for applications that demand mechanical degrees of freedom or optical isolation from the environment, a key requirement in the fabrication of both optical and mechanical resonators. Current fabrication techniques for suspended structures are limited to specific material systems, leading to a search for alternate nanomachining procedures.

U.S. Patent(s) Issued: US8999105B2