Porous Silicon as a Sacrificial Layer in Production of Silicon Diaphragms by Precision Grinding

Thermal Properties of Porous Silicon

“…PSi can be removed using different methods depending on the feature size and the porosity of the layer (Prochaska et al 2002). For example, nanoporous silicon can be removed by one of the following methods:…”

Porous Silicon Characterization and Application: General View

“…Silicon nitride can be easily deposited using standard low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD) methods, but the thickness of a stoichiometric Si 3 N 4 layer deposited by those methods is limited to 200 nm as a result of residual stress building up (Splinter et al 2001). Moreover, stripping this mask to the porous silicon layer obtained after the etching may be difficult without damaging PSi; wet etching of nitride mask necessitates prolonged immersion of nanoporous layers in orthophosphoric acid at 165°C or HF solution (Prochaska et al 2002). No damage to porous layers was observed during mask removal by dry etching.…”

Investigation of precision grinding process for production of silicon diaphragms

“…Figure 11 illustrates the dependence of the diaphragm bending magnitude on the two factors. 11 The presence of an interfacial oxide creates a gap between the surface of the porous silicon and the surface of the opposite wafer. During grinding this allows some deflection of the diaphragm and consequently postgrind bending of the diaphragm.…”