In a method of processing a semiconductor device, a silicide-blocking layer may
be formed over a semiconductor material. After defining the silicide-blocking layer,
impurities may be implanted into portions of the semiconductor material as defined
by the silicide-blocking layer. After the implant, silicide may be formed in a
surface region of the semiconductor material as permitted by the silicide-blocking
layer. Regions of the impurity implant may comprise boundaries that are related
to the outline of the silicide formed thereover. In a further embodiment, the implant
may define a base region to a thyristor device. The implant may be performed with
an angle of incidence to extend portions of the base region beneath a peripheral
edge of the blocking mask. Next, an anode-emitter region may be formed using an
implant of a substantially orthogonal angle of incidence and self-aligned to the
mask. Epitaxial material may then be formed selectively over exposed regions of
the semiconductor material as defined by the silicide-blocking mask. Silicide might
also be formed after select exposed regions as defined by the silicide-blocking
mask. The silicide-blocking mask may thus be used for alignment of implants, and
also for defining epitaxial and silicide alignments.
