Improved SiGe power HBT characteristics by emitter layout

A new emitter finger layout in SiGe HBT to reduce thermal-coupling is presented in this study. By redistributing the emitter fingers of various SiGe HBTs, the thermal resistance reduces significantly from 133 to 88 K/W under room temperature. Thus, in dc performance, output conductance increases from −2.0 to −1.6 mA/V. In ac performance, the fMAX shows an improvement over 10%. In power performance, the linear power gain, P1 dB and PAEatP1dB increase by 0.5 dB, 1.5 dB and 6.2% at 1.8 GHz, respectively.