Creation of Nanometer-Sized Features in Polysilicon Using Fusing

Current microfabrication systems can achieve resolutions of approximately 0.1μm. We present physical methods for creating structures with length scales and characteristic dimensions significantly below current fabrication resolutions. These structures, themselves fabricated in conventional, gross-resolution (greater than 2μm) semiconductor facilities, undergo structural change to create features below the lithography limits of the fabrication process. These devices — dog-boned microfabricated polysilicon fuses — are heated just below melting, and a small perturbation current heats a narrow, necked region of the beam, resulting in fusing. Infrastructure has already been constructed to create gross-resolution structures in microfabrication. Novel processes and mechanisms are needed to utilize these resolutions and create structures capable of addressing biological systems, functioning quantum mechanically, use single electrons, or require extreme speeds.

A Modified Tension Test

The present paper deals with a modified tension test with experimental results for SAE 1020, SAE 1215, and OFHC Cu of standard 12.8 mm (0.505 in.) dia test bars. The tension test was interrupted at predetermined intervals in order to remove excess material from the gage sections after necking had commenced, or to subject the gage sections to a drawing operation in order to keep the difference between the neck diameters and the gage section diameter as small as possible for the purpose of reducing the triaxiality of the stresses in the necked region. The tests showed that the triaxiality could be reduced for SAE 1215 and OFHC Cu by machining the gage section. However, as expected and shown for one series of tests with ETPC Cu, the drawing operations were more effective because of work hardening of the gage sections.