Advances in Selective Area Laser Deposition of Silicon Carbide

Selective Area Laser Deposition (SALD) is a Solid Freeform Fabrication (SFF) technique which uses a scanning laser beam to produce solid material by locally decomposing a gas precursor. In this work, a focused C02 laser beam strikes a substrate in the presence oftetramethylsilane (TMS) or diethylsilane (DES), producing silicon carbide objects with high density and no binder phase. Recent investigation has yielded growth rates up to 2.7mlnJmin in the beam area, and has eliminated previously noted contamination ofthe optics by a byproduct which mass spectroscopy identifies as silicon dioxide. This paper reviews a cause of non-uniform growth and delTIOnstrates the addition of hydrogen and reduced scan speeds to lTIake lTIultilayer parts. In addition, it presents a lTIethod for in-situ measurement of height of deposited material.Mechanical Engineerin