The temperature dependence of double-mesa SiGe HBTs is investigated. The different bandgaps of the hetero junctions cause the characteristic temperature behavior of HBTs. A straight forward method to extract the effective bandgaps of base, emitter and collector is explained. The thermal resistance is calculated and a dependence on temperature and on dissipated power similar to GaAs is found. For modeling purposes, as a first approximation, a constant value for the thermal resistance can be assumed. Finally a complete large-signal modeling is done using a VBIC model. The excellent agreement of measured and simulated performance of 47 GHz and 50 GHz oscillators validates our results.     «

The temperature dependence of double-mesa SiGe HBTs is investigated. The different bandgaps of the hetero junctions cause the characteristic temperature behavior of HBTs. A straight forward method to extract the effective bandgaps of base, emitter and collector is explained. The thermal resistance is calculated and a dependence on temperature and on dissipated power similar to GaAs is found. For modeling purposes, as a first approximation, a constant value for the thermal resistance can be assum...     »