Gas-Phase Laser-Induced Pyrolysis of Tapered Microstructures

Gas-phase Selective Area Laser Deposition (SALD) is a useful freeform fabrication tool for the prototyping of simple three-dimensional microstructures. Using this method, slender graphite and nickel rods of various diameters were grown from ethylene and nickel tetracarbonyl, respectively. By varying the laser power during growth, tapered cone-like structures were also generated. Rod diameters and material morphology were correlated with the SALD process parameters to demonstrate the mechanisms through which steady-state rod growth occurs--and through which it can be controlled. Rods, and other similar microstructures, have many useful applications, and are preliminary building blocks for further modelling and development of the SALD process as a micromachining tool. Keywords: Laser chemical vapor deposition, LCVD, SALD, 3-dimensional growth, micro fabrication, rapid prototyping, micro electro mechanical systems, pyroiysis, graphite, nickel, rods, cone.