Gas-selective membrane and method of its production
A membrane selectively permeable to light gases comprises a membrane body formed by a first plate and a second plate. The second plate comprises a thin layer that is selectively gas-permeable. In the region of windows, this layer is exposed. There, support is provided by a porous bottom wall in the first plate or by narrow bores in the second plate. A heating device causes a radiation heating of the windows.
1. A method for the manufacture of a membrane having gas-permeable windows, the method comprising the following steps:
manufacturing a first plate from silicon,
forming recesses or passages in the first plate,
applying a second silicon plate comprising a selectively gas-permeable layer of a silicon material onto the first plate,
forming recesses in the second plate, wherein the recesses in the second plate are at least partially overlapping with the recesses or passages in the first plate, such that both plates form a membrane body with windows that each include the selectively gas-permeable layer; and
wherein the recesses of the first plate comprise bottom walls that are porosified and pervious to gas.
2. The method of claim 1 , wherein the forming of recesses or passages is done by etching.
3. The method of claim 2 , wherein the selectively gas-permeable layer is made of SiO 2 and forms a bottom wall of the second plate.