Monte-Carlo study of the nonstationary transport in Si-SiGe HJBTs
The authors report a study by Monte-Carlo simulation of an npn HBT with a Si1-xGex base. The injection of ballistic electrons over an abrupt emitter-base heterojunction allowed the base transit time to decrease to 0.2 ps. However, the interest of this ballistic transport was limited by the following two-dimensional phenomena: the defocalization of the emitter current and the Kirk effect.