In this work we present migration phenomenon of throughholes in silicon membranes. The sealing of through-holes in hydrogen ambient at high temperature (1130°C) with various dimensions and annealing time durations was investigated in both singlecrystalline silicon (sc-Si) and poly-crystalline silicon (poly-Si) membranes. The sealing process in silicon was observed as highly dependent on local crystal grain geometry, leading to more distributed, unpredictable migration rates and shape evolutions in poly-Si compared to holes in sc-Si. These findings can be leveraged in fabrication processes that require a balance between silicon migration and deposition.
A novel process for the preparation of thick porous silicon layers having very high porosities is proposed. Starting with thick layers of intermediate porosity the porosity is further increased in an additional step. This is done by means of controlled partial oxidation of the silicon skeleton followed by selective removal of the oxide film in an HF vapor phase etching process. Due to this, porosities beyond 90% are accessible since any further liquid phase contact is avoided and therefore no additional drying steps are necessary.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.