Bipolar transistor with extrinsic stress layer

摘要

A method of increasing mobility of charge carriers in a bipolar device comprises the steps of: creating compressive strain in the device to increase mobility of holes in an intrinsic base of the device; and creating tensile strain in the device to increase mobility of electrons in the intrinsic base of the device. The compressive and tensile strains are created by forming a stress layer in close proximity to the intrinsic base of the device. The stress layer is at least partially embedded in a base layer of the device, adjacent an emitter structure of the device. The stress layer has different lattice constant than the intrinsic base. Method and apparatus are described.