Forward and inverse mode Early voltage dependence on current and temperature for advanced SiGe-pnp on SOI

We present a comprehensive investigation of Early voltage (VA) versus drive current dependence for SiGe-pnp bipolar transistors fabricated on thick-film SOI, operating in normal (forward) and inverse (reverse) mode bipolar conditions. Thermal resistance effects are separated by comparing HBT devices with different thermal footprints for SiGe-pnp transistors characterized in normal and inverse mode of operation. Results show that the emitter and collector resistances play a significant role in the Early voltage characteristics. TCAD simulations are used to explain the observations, showing agreement to experimental data measured between -60°C to +200°C.