Direct Bonding of Oxidized Cavity Wafers

In MEMS fabrication BSOI substrates have become more and more common. SOI MEMS structures are typically released by etching of sacrificial oxide layer. This technology has some constraints which may partly be avoided by using SOI wafers with buried cavities [1]. In this technology MEMS structures are typically released with DRIE etching. Sometimes an etch stop layer is preferred to prevent etching from continuing at the bottom of the cavity. Thermal oxidation of wafer with cavities is one way to form an etch stop layer. The goal of our research is to study the effects of thermal oxide etch stop layer on wafer bondability.