TEMPERATURE-DEPENDENT MODEL FOR HOLE EFFECTIVE-MASS IN HEAVILY-DOPED P-TYPE SIGE

As a consequence of compressive strain and alloying, the hole effectiv e mass inp-type strained SiGe differs significantly from its Si value. Influencing the carrier concentrations in the base, the hole effectiv e mass affects the base transport properties of npn SiGe HBTs. A new m odel for hole effective mass is presented in this work, which takes in to consideration the dependence on temperature, doping concentration a nd germanium fraction. The model is based on experimental data and the oretical studies of the valence band structure supported by the detail ed numerical analysis of hole effective mass. It is suitable for effic ient analysis and optimization of SiGe HBTs, and can be tuned to the m easurements of carrier transport. The model is valid in the temperatur e range from 77K to 300K, for doping concentrations up to 10(20)cm(-3) and for germanium fractions up to 0.2.