The broader impact of this Small Business Technology Transfer (STTR) Phase I project is the development of a 3D fabrication technology that provides the benefits of 3D printing (i.e., rapid prototyping, the creation of complex 3D structures, etc.) for high-quality, single-crystal silicon and silicon carbide. The technique will compete with traditional photolithography-based semiconductor manufacturing for applications such as MicroElectroMechanical System (MEMS) sensors such as accelerometers in cell phones and vehicle airbags, silicon photonics used in optical communications networks and data centers, microfluidics for drug-discovery and other biomedical applications, and interposers for 3D integration of integrated circuits. The 3D fabrication technique is superior to traditional semiconductor fabrication in three ways: 1) Up to a 100X reduction in prototype manufacturing time, resulting in cost savings and increasing the speed of R&D cycles; 2) Significantly reducing CapEx by replacing multiple fabrication tools with one single tool; and 3) Creating complex 3D structures directly, significantly improving on the limited extruded 2D geometries available from photolithography-based fabrication. Additionally, the 3D manufacturing capability can be extended to macro-scale components and impact industries such as energy conversion and aerospace by providing complex 3D structures made from single-crystal silicon carbide for extreme high-temperature operation. The proposed project combines elements of advanced nonlinear optics with electrochemical etching of semiconductor materials to enable the 3D manufacturing technique for single-crystal silicon and silicon carbide. While the fundamental physical mechanism has been demonstrated in work leading up to this project, there are important questions remaining about control of the material removal process, the surface quality of the final structure, and the rate at which material can be removed. These questions need to be addressed to understand which applications of the 3D manufacturing technique are commercially viable. The technical objectives and tasks for this project have been designed to answer these questions through careful experimentation and, with the data obtained, identify the most promising applications to pursue. Experiments for both silicon and silicon carbide will be conducted that explore a range of permutations of input parameters and variables for the 3D manufacturing process. Results of these experiments will be studied and characterized to identify optimal etch parameters and the etch results possible with those etch parameters. At the conclusion of this Phase 1 STTR project, the capabilities of the 3D fabrication technique will be better understood and a clear path for commercializing the capability will be identified. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
