Fabrication of submicrometer-sized electrical probes from glass-metal composite using a laser-based micropipette puller.

摘要

Submicron electrical probes were fabricated from glass capillary tubes and thin metal wires. These probes have applications in measuring the electrical properties of materials. The probes were fabricated in a CO2 laser based micropipette puller. Empty silica tubes have been pulled to outer diameters of less than 100 nm (outer diameter) and wire-filled glass tubes have been pulled to less than 500 nm (outer diameter). The glass absorbs the laser energy and heat is transferred to the metal wire. When both the glass and metal had softened sufficiently, the clamps at each end of the tube apply tensile force. This process draws the glass and metal down together, and results in two tapered micropipettes with a core of metal inside. The metal acts as an electrically conductive channel, which is insulated by the surrounding glass. After the fabrication method of the microprobes was established, the probes were integrated into a modified four-point probe measurement system. In this system, the microprobe is mounted onto a translation stage, and is scanned across the surface of the material, while the other three probes remain static. This allows for measurement of the electrical conductance of the sample and the contact resistance between the sample and the current leads. The fabrication issues of these probes and their applications are presented.