In situ investigation of 75 MeV boron and 100 MeV oxygen ion irradiation effects on 50 GHz silicon–germanium heterojunction bipolar transistors

First-generation (50 GHz) silicon–germanium heterojunction bipolar transistors (SiGe HBT) were irradiated with 75 MeV boron ions and 100 MeV oxygen ions. The aim of the present investigation is to study the degradation of current–voltage (I–V) characteristics due to different linear energy transfer ions. The in situ I–V characteristics were measured before and after ion irradiation are forward mode and inverse mode Gummel characteristics, excess base current and current gain. It was found that the oxygen ion-irradiated SiGe HBT showed slightly more degradation when compared with boron ion-irradiated devices. The damage constant was calculated using the Messenger–Spratt equation, which confirmed more degradation in the case of oxygen ion-irradiated HBTs.