A novel device structure using a shared-subcollector, cascoded inverse-mode SiGe HBT for enhanced radiation tolerance

We present a novel device structure using an inverse-mode, cascoded (IMC) SiGe HBT for improved tolerance of heavy ion irradiation. The cascoded SiGe device consists of a forward-mode, common-emitter SiGe HBT cascoded with a common-base inverse-mode SiGe HBT, with the subcollector region of the two devices shared. The device was fabricated in both first and third-generation, commercially-available SiGe HBT technologies. The third-generation IMC device was measured to have over 20 dB of current gain and over 30 dB of power gain at 10 GHz. In addition, the measured total dose radiation response and simulated current transients are presented. These results demonstrate the potential use of these devices in high-speed circuits intended for operation in space or other extreme environments.