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In this paper, a temperature-switching approach (TSA) was used to evaluate low-dose-rate (LDR) ionizing radiation effects on single-event transients (SETs) in linear bipolar circuits. The experimental results show that the SET phenomenon of bipolar circuits after irradiation using a TSA with 3-rad(Si)/s dose rate is basically consistent with the SET phenomenon of bipolar circuits after LDR of 0.01-rad(Si)/s irradiation, which is obviously different from the SET phenomenon of bipolar circuits after the high-dose-rate of 10-rad(Si)/s irradiation. The TSA for evaluating the enhanced LDR sensitivity (ELDRS) of bipolar devices can be applied to the rapid evaluation of the SET effect of the bipolar circuits with LDR irradiation. [ABSTRACT FROM AUTHOR]

A temperature-switching irradiation (TSI) sequence has been developed that is based on a first-principles understanding of interface-trap buildup and annealing. The dynamics of interface-trap buildup and annealing during elevated temperature irradiation are described in detail to provide background, context, and enhanced understanding of the TSI method. The method is shown to be a practical and conservative test for enhanced low-dose-rate sensitivity (ELDRS) in linear bipolar devices and ICs. Examples of TSI sequences are shown for target doses up to 200 krad(Si), a range of great practical interest for space applications. The method can be adapted for higher dose applications via similar approaches. Devices that do not exhibit ELDRS respond similar to TSI and high-dose-rate irradiation. [ABSTRACT FROM AUTHOR]

Effect of total ionizing dose (TID) on single-event upset (SEU) hardness of 130 nm partially depleted (PD) silicon-on-insulator (SOI) static random access memories (SRAMs) is investigated in this paper. The measurable synergistic effect of TID on SEU sensitivity of 130-nm PD SOI SRAM was observed in our experiment, even though that is far less than micrometer and submicrometer devices. Moreover, SEU cross section after TID irradiation has no dependence on the data pattern that was applied during TID exposure: SEU cross sections are characterized by TID data pattern and its complement data pattern are decreased consistently rather than a preferred state and a nonpreferred state as micrometer and sub-micrometer SRAMs. The memory cell test structure allowing direct measurement of static noise margin (SNM) under standby operation was designed using identical memory cell layout of SRAM. Direct measurement of the memory cell SNM shows that both data sides’ SNM is decreased by TID, indicating that SEU cross section of 130-nm PD SOI SRAM will be increased by TID. And, the decreased SNM is caused by threshold shift in memory cell transistors induced by “radiation-induced narrow channel effect.” [ABSTRACT FROM AUTHOR]

Enhanced low dose rate sensitivity (ELDRS) in different process Silicon–Germanium heterojunction bipolar transistors (SiGe HBTs) is investigated. Low and high dose rate irradiations are performed to evaluate the ELDRS of SiGe HBTs manufactured by Tsinghua University (THU). THU SiGe HBTs experience significantly low dose rate sensitivity than that of IBM 8HP SiGe HBTs and behave a “true” dose rate effect. TCAD models were used to explicate the microcosmic structure in THU and IBM 8HP SiGe HBTs. Comparison and discussion show that different SiGe processes may involve different HBT structures and device designs which are the critical influence of ELDRS effect. The different responses of ELDRS should be first attributed to the device structure and design in nature, particularly the geometry of emitter–base junction and the isolation structure. [ABSTRACT FROM PUBLISHER]

The effect of bias condition on total ionizing dose (TID) of Silicon–Germanium heterojunction bipolar transistors (SiGe HBTs) is investigated. The SiGe HBTs are set at forward, saturated, cutoff, and all-grounded biases during ^60\Co\gamma irradiation. After each irradiation stops, the forward Gummel characteristic and inverse Gummel characteristic are measured, and a 3-D simulation of TID for SiGe HBT is performed. The mechanism of TID in different bias conditions is obtained by analyzing normalized excess base current. The results show that the TID damages are different at various irradiation biases of the SiGe HBT, and the worst bias between forward and inverse Gummel characteristics exhibits inconsistently. The reason could be attributed to different defects produced and accumulated in oxide layers by irradiation at various bias conditions. To be specific, the oxide trap charges (${{\hbox{N}}_{\rm ot}}$) in emitter/base (E/B) Spacer is important to the forward Gummel characteristic, yet the ${{\hbox{N}}_{\rm ot}}$ in LOCOS determines the inverse Gummel characteristic. However, after long time irradiation, the interface states (${{\hbox{N}}_{\rm it}}$) both in E/B Spacer and LOCOS dominate the damage to the SiGe HBT despite in forward Gummel mode or inverse Gummel mode. [ABSTRACT FROM AUTHOR]