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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