Calibration of 1D doping profiles of SiGe HBTs

Due to the miniaturization in microelectronics and corresponding steep doping profiles, it is increasingly difficult to obtain reliable results from SIMS measurements. This paper aims at providing a guideline for calculating unknown profile information by means of TCAD simulations using electrical reference data. The corresponding procedure has been applied to both measurements and synthetic TCAD reference data of SiGe HBTs. An extensive geometry scalable parameter extraction was performed for obtaining reliable measured reference data of the 1D transistor. The methodology modifies the doping of the space charge regions of a 1D transistor to the extracted area related BE and BC capacitances. To adjust the internal base doping profile, measured sheet resistance, zero-bias hole charge, and area related transit time are used as reference. Furthermore, the transfer current and the normalized transconductance are very sensitive to the shape of the Germanium profile and can serve as reference. The methodology was verified with TCAD data first and then applied to measurements.