Investigation of Thermal Crunching Effects in Fishbone-Type Layout Power GaAs-HBTs

Thermal current crunching in power HBTs is investigated by numerical simulation. Compact electro-thermal models are connected in parallel, thermal interaction is accounted for by a thermal resistance matrix. It turnes out that the dominant effect in HBTs of fishbone-type layout is that half of the HBT is effectively switched off. This can only be simulated by a slightly asymmetric model.