Verfahren zur Herstellung eines dünnen Membrans oder Balkens aus Silicium.

摘要

A method is disclosed for forming thin, suspended membranes of epitaxial silicon material. Silicon oxide strips (12) having a predetermined thickness are first formed on a silicon substrate (10). A gap (14) provided between adjacent pairs of strips (12) is preferably less than or equal to about 1.4 times the thickness of the silicon oxide strips (12). The underlying silicon substrate (10) is exposed within these gaps (14) in the silicon oxide layer, whereby the gaps (14) provide seed holes for subsequent epitaxial growth from the silicon substrate (10). Epitaxial silicon is grown through the gaps (14) and then allowed to grow laterally over the silicon oxide strips (12) to form a continuous layer (20) of epitaxial silicon over the silicon oxide strips (12). The backside of the silicon substrate (10), i.e., the surface opposite the surface having the silicon oxide strips (12), is then masked to delineate the desired diaphragm and microbridge pattern. The silicon is etched conventionally from the backside of the silicon substrate (10). Etching is terminated substantially automatically by the presence of the silicon oxide strips (12). The thin, single crystal silicon membranes thus formed are suitable for use as diaphragms and microbridges in a microaccelerometers or a pressure sensor.