Thin film membrane structure

Abstract

A membrane structure comprising a silicon film having a grain structure including grains defining pores therebetween.

1 . (Cancelled).  
     
     
         2 . The structure of  claim 27  wherein the maximum cross-sectional dimension of any one grain is approximately equal to the thickness of the silicon layer.  
     
     
         3 . The structure of  claim 27  wherein a lateral dimension of any pore is less than that of any grain.  
     
     
         4 . The structure of  claim 27  wherein a lateral dimension of the pores is between about 10 and 50 nanometers.  
     
     
         5 . The structure of  claim 27  wherein the thickness of the silicon layer is less than or equal to about 150 nanometers.  
     
     
         6 . The structure of  claim 27  wherein the thickness of the silicon layer is between about 50 and 150 nanometers.  
     
     
         7 . The structure of  claim 27  wherein the roughness of the silicon layer is approximately equal to its thickness.  
     
     
         8 . The structure of  claim 27  wherein the silicon layer forms a filter.  
     
     
         9 . The structure of  claim 27  wherein the silicon layer is conformal to an underlying surface.  
     
     
         10 . The structure of  claim 27  further including a structural layer to support the silicon layer.  
     
     
         11 . The structure of  claim 27  further including a conformal layer formed on the silicon layer to provide a selected chemical or biological function.  
     
     
         12 - 26 . (Cancelled).  
     
     
         27 . A structure comprising: a silicon layer having a grain structure including grains defining pores therebetween wherein the grains have an approximately hemispherical shape and the silicon layer has a controlled residual stress within a range of between about −100 to 100 mega-Pascals  
     
     
         28 . The structure of  claim 27  wherein the maximum diameter of any one grain does not exceed the thickness of the silicon layer.  
     
     
         29 . A structure comprising: a silicon layer having a grain structure including grains of approximately hemispherical shape defining pores therebetween wherein the parameters used to form the silicon film were controlled to insure that the silicon film has a residual stress of between about −100 to 100 mega-Pascals.  
     
     
         30 . The structure of claims  27  or  29  wherein the residual stress is between about −50 to 50 mega-Pascals.