PATENT COVER GRAPHIC

United States Patent 3,990,925
November 9, 1976

Removal Of Projections On Expitaxial Layers
William Charles Erdman

Filed March 31, 1975
Image of US PATENT 3,990,925

Abstract of the Disclosure

A method for removing projections from the surface of epitaxially-deposited semiconductor layers is described. These projections can adversely affect the results of photolithographic processing. The method comprises forming an oxide layer on the surface and mechanically fracturing the oxide-coated projections. In the ensuing step anisotropic semiconductor etchants are applied to the surface to remove the projections selectively.
Figure descriptions: cover graphic

  • schematically represents a cross section of the wafer during one step of one embodiment in accordance with the invention. 

 Citations [54]:
  
3,699,644  10/1972  Cocca
3,718,514  02/1973  Erdman et al
3,738,881  06/1973  Erdman et al
3,783,044  01/1974  Cheskis et al
3,838,501  10/1974  Umbaugh et al
National Museum of American History
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