Chemistry Reference
In-Depth Information
conditions, and sample preparations. The formation of hillocks significantly reduces the
etch rate in the (100) direction.
706
Addition of
to
solution acts to suppress
the formation of hillocks.
Hydrazine.
As a close relative of aqueous hydrazine solutions have
also been investigated to a significant extent. Hydrazine, may be thought of as
derived from by replacing a H atom by the group. A hydrazine-water (1:1)
solution shows some desirable characteristics.
708
The etch rate of oxide, nitride, and
most metals in hydrazine solutions is very low. No precipitation occurs during etching
and the etching produces good surface quality and sharply defined corners. This etchant,
however, has a low anisotropic selectivity and is also toxic.
