Fabrication of SiO_2-based microcantilevers by anisotropic chemical etching of (100) single crystal Si

摘要

The undercutting process of thermal SiO_2 microcantilevers with different orientations on (100) Si wafer was studied. The silicon substrate was removed by anisotropic chemical etching with a 25 wt. % aqueous solution of TMAH or a 30 wt. % aqueous KOH solution at 80 ℃. It was found that <110> oriented cantilevers were undercutting frontally along the length and <100> oriented cantilevers experience undercutting along the width of the cantilever, which is a less time consuming process. The studies showed that the <100> orientation of SiO_2 microbridges enables theirs fabrication on a <100> oriented Si substrate.