Chemistry Reference
In-Depth Information
For a given etching system, there is a steady-state roughness. If the initial rough-
ness is smaller than this roughness, the roughness of the etching surface tends to
increase, and if the initial roughness is larger than the steady-state roughness, it tends
to decrease. Generally, as-received silicon wafers have a very small surface roughness,
and in most etchants the roughness tends to increase as etching proceeds. In the etching
in 25% KOH at 70°C, a steady-state roughness is reached at about 4h for the (111)
surface and much longer for the (100) surface.
1000
Crystallographic Characters and Formation of Hillocks.
The surface rough-
ness of silicon single crystals has clear crystallographic characteristics as illustrated in
