An investigation of electro-thermal instabilities in 150 GHz SiGe HBTs fabricated on SOI

We investigate, for the first time, the electro-thermal stability of 150 GHz SiGe HBTs that were optimized for bulk-Si and then fabricated on SOI substrates to enable a direct comparison. AC, DC and pulsed measurements are used to characterize the devices and study the onset of electro-thermal instabilities. Implications of electro-thermal feedback induced instabilities resulting from self-heating are discussed, along with consequent electrical biasing constraints imposed on the device. Figures-of-merit are proposed as effective tools for comparing devices with strong self-heating effects. TCAD is used to predict the implications for performance scaling and BiCMOS technology development for SiGe on SOI platforms.