Operation of inverse mode SiGe HBTs and ultra-scaled CMOS devices in extreme environments

Cryogenics;HBT;Bipolar transistors;Radiation

Appaswamy, Aravind ; Electrical and Computer Engineering

University:Georgia Institute of Technology

Department:Electrical and Computer Engineering

关键词: Cryogenics;    HBT;    Bipolar transistors;    Radiation;   

Others  :  https://smartech.gatech.edu/bitstream/1853/33970/1/appaswamy_aravind_c_201005_phd.pdf

美国|英语

来源: SMARTech Repository

【 摘 要 】

The objective of this work is to investigate the performance of SiGe HBTs and scaled CMOS devices in extreme environments. In this work, the inverse mode operation of SiGe HBTs is investigated as a potential solution to the vulnerability of SiGe HBTs to single event effects. The performance limitations of SiGe HBTs operating in inverse mode are investigated throughan examination of the effects of scaling on inverse mode performance and optimization schemesfor inverse mode performance enhancements are discussed and demonstrated. In addition theperformance of scaled MOSFETs, that constitute the digital backbone of any BiCMOS technology, is investigated under radiation exposure and cryogenic temperatures. Extreme environments and their effects on semiconductor devices are introduced inChapter 1. The immunity of 90nm MOSFETs to total ionizing dose damage under protonradiation is demonstrated.Inverse mode operation of SiGe HBTs is introduced in Chapter 2 as a potential radiationhard solution by design. The effect of scaling on inverse mode performance of SiGe HBTs isinvestigated and the performance limitations in inverse mode are identified.Optimization schemes for improving inverse mode performance of SiGe HBTs are discussed in Chapter 3. Inverse mode performance enhancement is demonstrated experimentally in optimized device structures manufactured in a commercial third generation SiGe HBT BiCMOS platform. Further, a cascode device structure, the combines the radiation immunity of an inverse mode structure with the performance of a forward mode common emitter device is XIV discussed. Finally, idealized doping profiles for inverse mode performance enhancement is discussed through TCAD simulations.The cryogenic performance of inverse mode SiGe HBTs are discussed in Chapter 4. A novel base current behavior at cryogenic temperature is identified and its effect on the inverse mode performance is discussed.Matching performance of a 90nm bulk CMOS technology at cryogenic temperatures isinvestigated experimentally and through TCAD simulations in Chapter 5. The effect of variousprocess parameters on the temperature sensitivity of threshold voltage mismatch is discussed.The potential increase of mismatch in subthreshold MOSFETs operating in cryogenictemperatures due to hot carrier effects is also investigated.