Extreme Environment Operation of Thick-Film SOI SiGe HBTs in both High Temperature & Radiation-rich Environments

Abstract

The objective of this work is to characterize and investigate the effect of extreme environments, such as high temperature (up to 300$^\circ$C) and radiation, on the response of thick-film SOI SiGe HBTs. Two different SiGe platforms are explored in this work with one aimed at RF applications (180 GHz f\textsubscript{max}) and the other aimed at high performance and high voltage (up to 48V) analog applications (20 GHz f\textsubscript{max}). To the best of the author's knowledge, this is the first look into the 300$^\circ$C operation of thick-film SOI SiGe HBTs and the effect of TID on a high-voltage complementary SiGe platform.

Chapter 1 presents a brief overview and summary of the SiGe technology. The effect of incorporating Ge in a Si BJT is emphasized and is quantitatively described.

Chapter 2 presents the high temperature (to 300$^\circ$C) DC and AC performance of a $>$ 100 GHz f\textsubscript{T}/f\textsubscript{max} SiGe HBTs on thick-film SOI. Metrics such as current gain ($\beta$\textsubscript{F}), BV\textsubscript{CEO}, M-1, f\textsubscript{T}, f\textsubscript{max} are extracted from 24$^\circ$C to 300$^\circ$C and compared with a bulk SiGe HBT platform. The results demonstrate that while there are degradation to key device metrics at high temperatures, the devices are still usable over a wide temperature range. Additionally, while SOI is known for its high thermal resistance, it is demonstrated that the device is constrained by electrical effects rather than thermal effects at higher temperatures, which should therefore yield acceptable reliability. This work was presented at the IEEE Bipolar/BiCMOS Circuits and Technology Meeting 2015 \cite{omprakash_2015}.

Chapter 3 presents the impact of total ionizing dose (TID) on a high-voltage (36V) complementary SiGe on SOI technology, including the effects of irradiation and bias on the device oxides and the implications on forward and inverse-mode device operation. The results indicate a multi-Mrad tolerance to TID similar to other SiGe HBTs, however, they illustrate a slightly anomalous behavior at high injection due to a decrease in collector resistance. A clear difference between forward mode and inverse mode response is also observed with bias. This work was submitted for the IEEE Nuclear and Space Radiation Effects Conference 2016.

Chapter 4 provides a summary of the contributions presented in this thesis. Additionally, it outlines the future work to be done based on the current research.