CPC H01L 21/76254 (2013.01) [H01L 21/263 (2013.01); H01L 21/324 (2013.01); H01L 21/76251 (2013.01)] | 18 Claims |
1. A substrate, comprising:
a useful layer affixed to a support substrate;
wherein a surface of the useful layer located on a side of the useful layer opposite the support substrate comprises:
a first region comprising a first surface roughness, the first region located proximate to a geometric center of the surface, the first region occupying a majority of an area the surface; and
a second region comprising a second, higher surface roughness, the second region located proximate to a periphery of the surface, the second region occupying a minority of the area of the surface;
wherein the first region is at least substantially free of periodical patterns in variations of surface height, and the second region comprises periodical patterns in variations in surface height.
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