Large area deposition in high vacuum with high thickness uniformity

Abstract

The invention relates to an effusing source for film deposition made of a reservoir comprising one hole characterized by the fact that the hole diameter is less than one order of magnitude than the mean free path of the molecules determined by the pressure and its thickness is at least one order of magnitude smaller than the diameter. Preferably the source has several holes.

1 . Effusing source for film deposition made of a reservoir comprising one hole characterized by the fact that the hole diameter is less than one order of magnitude than the mean free path of the molecules determined by the pressure and its thickness is at least one order of magnitude smaller than the diameter.  
   
   
       2 . Effusing source according to  claim 1  designed to impinge effusing molecules on a deposition area situated at a distance of at least one order of magnitude larger than the hole diameter.  
   
   
       3 . Effusing source according to  claim 1  designed in such a way that the ratio “number of molecules impinging on a deposition area” versus “total number of effusing molecules” is more than 20%.  
   
   
       4 . Effusing source according to  claim 1  wherein the source is designed in such a way that the distribution of impinging molecules on a deposition area in the molecular regime only depends on the source relative position and on its molecular angular distribution.  
   
   
       5 . Effusing source according to  claim 1  wherein it includes a gas phase collisions forbidden volume and pumping apertures in the surface of said volume to reduce the contribution of walls surface scattered molecules for certain angles.  
   
   
       6 . Effusing source according to  claim 1  comprising several holes.  
   
   
       7 . Effusing source according to  claim 6  wherein the holes are distributed on a ring or on several rings with a tilt angle.  
   
   
       8 . Effusing source according to  claim 6  wherein the holes are distributed on a spherical surface such as an hemisphere that has a diameter of at least one order of magnitude smaller than the distance of the source to the deposition area.  
   
   
       9 . Effusing source according to  claim 6  with under-cosine distribution of sources for small angles and over-cosine distribution of holes for larger angles.  
   
   
       10 . Effusing source according to  claim 6  with fractal distribution of holes.  
   
   
       11 . Effusing source according to  claim 10  with asymmetric fractal distribution of holes.  
   
   
       12 . Effusing source according to  claim 6  with variable angular distribution of holes and without any moving part.