TEM-investigations for macropore-formation
   
   
This work was a cooperation with the group of Prof. Dr. Jäger (Center of Mircoanalyse at the University of Kiel)
Center of Microanalye in Kiel
   
   
TEM-investiagtions for macropore-formation on n-type-silicon
  This mircograph shows an overview on macropores and dendritic pores (break-through-pores) on n-type-silicon etch under backside.illumination. It is obviously that the dendritic pores growth anisotropic - the growth-direction is the <100>-direction.
       
       
  The macropore-walls show (111)-facetts. This facetts can be explained in the modell for macropore-formation as surface with an slow kinetic for H-termination.
       
       
  At the tips of the dendritic-pores Spannunsgkonstrate were found. It was shown with EDX-analyse that an silicon-oixde was build at the pore tips. The oxid-formation is an part of the formation modell.
       
       
  The dendritic pores were formed by intercalating (111)-oktaeder. The (111) is the plane with the lowst kinetic for the passivation.
       
       
  A schematic picture of an dendritic pore. The (111)-okteader were shown. The size of the oktaeder should by a function of the etch-potential and the H-concentration.
       
       
TEM-investigations for macropore-formation on p-type-silicon
  We have published the first TEM-mircographs on macropores in p-type-silicon.  
       
       
  This micrograph shows macropores on p-type-silicon in plane-view. The pores were filled with mesoporous silicon. The lack of the oxidizing reagent causes this filling (see theorie-part).
       
       
  The pore-tip of a macropore in p-type.silicon etched in Acetonitril and HF. The inhomogenious pore tips hints to an inmhomogenious formation-reaction at the tip. This mircographs shows the current-burst at the tips.
    
   
     
  Corresponding to n-type-silicon (111)-facetts were found at the pore-walls on macropores in p-type-silicon. The (111) is the surface with the lowst passigvation velocity.