Enhanced Low Dose Rate Sensitivity (ELDRS) tests on advanced SiGe bipolar transistors for very high total dose applications

A new comprehensive method for assessing Enhanced Low Dose Rate Sensitivity (ELDRS) in bipolar transistors to be used for very high total doses is applied to an advanced SiGe HBT technology for its use in the ATLAS Upgrade at CERN. Conventional ELDRS assessment methods are combined with switched experiments (high/low dose rate), providing a way to verify the presence of ELDRS at very high doses in reasonable irradiation time. Additionally, an anomalous damage recovery has been found in transistors with saturated damage after further low dose rate irradiations. -- Highlights: • It has been demonstrated that the bipolar technology under study does not show ELDRS in the whole range of total doses studied. • The previous radiation hardness tests of a SiGe HBT technology have been validated. • A new ELDRS test strategy is presented for ELDRS in very high total dose applications. • An anomalous damage recovery has been observed in switched dose rate experiments in the saturation region