Ke. Puttick et al., TRANSMISSION ELECTRON-MICROSCOPY OF NANOMACHINED SILICON-CRYSTALS, Philosophical magazine. A. Physics of condensed matter. Defects and mechanical properties, 69(1), 1994, pp. 91-103
Silicon substrate slices in (111) or (001) surface orientation have be
en machined in two ways: precision ground by a diamond abrasive wheel
to a surface roughness R(a) approximate to 11 nm, or turned on a highl
y stiff single-point diamond turning machine to R(a) approximate to 0.
5 nm. Transmission electron microscopy of cross-sections of the machin
ed surfaces has established the following. (1) The mean depth of perma
nent damage in both cases lies in the range 100-400 nm. (2) In the gro
und specimens the damage depth is very variable, and the damage consis
ts of regions of well defined dislocation loops on several slip system
s, other regions with a very high density of irregular dislocation arr
ays, and occasional microcracks up to 500 nm deep which do not always
intersect the surfaces. Patches of amorphous silicon are also observed
. (3) Beneath the turned surfaces the damage appears more homogeneous,
consisting of dislocation loops predominantly on a single slip system
in any given region of the specimen.