Design, Fabrication, and Modeling of Indium Phosphide Double-Heterojunction Bipolar Transistors With Sub-Millimeter Wave Cutoff Frequency

82 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009.The subject of this work is the design and fabrication of heterojunction bipolar transistors based on InP and the III-V compounds compatible with epitaxial growth on this substrate. Scaling and compositional variations of the transistor material layers are studied with the goal of improving device bandwidth. The cutoff frequencies of double-heterojunction transistors are extended as high as 690 GHz while maintaining an off-state breakdown voltage greater than 3 V by using the InP/GaAsSb material system with a type-II energy band alignment. Chapter 1 of this work gives an overview of the relevant materials and device parameters. Material structure design and vertical scaling are discussed in Chapter 2. In Chapter 3, lateral process scaling and the sub-micron HBT fabrication process are presented. Chapter 4 details the material designs studied and the measured device results including sub-micron HBTs with record RF performance. Chapter 5 presents small-signal parameter extraction and modeling work. Future work in device design and fabrication is proposed in Chapter 6.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD