A method of forming a semiconductor device having two different strains
therein is provided. The method includes forming a strain in a first
region with a first straining film, and forming a second strain in a
second region with a second straining film. Either of the first or second
strains may be either tensile or compressive. Additionally the strains
may be formed at right angles to one another and may be additionally
formed in the same region. In particular a vertical tensile strain may be
formed in a base and collector region of an NPN bipolar transistor and a
horizontal compressive strain may be formed in the extrinsic base region
of the NPN bipolar transistor. A PNP bipolar transistor may be formed
with a compression strain in the base and collector region in the
vertical direction and a tensile strain in the extrinsic base region in
the horizontal direction.