EPI-MICROMACHINING

Epi-micromachining is a technology which allows micromechanical struct ures to be fabricated entirely in the epitaxial layer, which is the to p 2-10 mu m of the wafer. This technique has several advantages over e xisting technologies. The lateral dimensions of the devices are simila r to those of surface micromachining, which is a considerable improvem ent over traditional bulk micromachined structures. Epi-micromachining has the advantages over surface micromachining that: (1) the structur es are in the substrate, thus maintaining a planar structure; (2) it h as the possibility of using single crystal silicon as a mechanical lay er; and (3) it requires only a few additional processing steps. Severa l techniques for fabricating such structures have been presented in th e literature using both dry plasma and wet chemical etching. This pape r reviews these techniques for fabricating epi-micromechanical layers and includes compatibility considerations. (C) 1997 Elsevier Science L td.