Bipolar transistors employing an MIS junction for the emitter exhibit the very desirable properties of high operating frequency and/or high common emitter gains. The topic of this thesis is to investigate the usefulness of the MIS bipolar transistor in real applications. The experimental results show two possible limitations of the devices. The principal limitation is the inability of these devices to withstand moderate temperature stressing. The second limitation is the relatively high emitter series resistance. The principal degradation mode of these devices under temperature stressing is suggested to be the reduction of the thin insulating oxide. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

The objective of the dissertation is to combine the recent Mixed-Mode reliability stress studies into a single text. The thesis starts with a review of silicon-germanium heterojunction bipolar transistor fundamentals, development trends, and the conventional reliability stress paths used in industry, after which the new stress path, Mixed-Mode stress, is introduced. Chapter 2 is devoted to an in-depth discussion of damage mechanisms that includes the impact ionization effct and the selfheating effect. Chapter 3 goes onto the impact ionization effect using two-dimensional calibrated MEDICI simulations. Chapter 4 assesses the reliability of SiGe HBTs in extreme temperature environments by way of comprehensive experiments and MEDICI simulations. A comparison of the device lifetimes for reverse-EB stress and mixed-mode stress indicates different damage mechanisms govern these phenomena. The thesis concludes with a summary of the project and suggestions for future research in chapter 5.