Development of silicon germanium HBT's and micromachined passive components for monolithic microwave integrated circuits

SiGe heterojunction bipolar transistors (HBT's) and micromachined lumped passive components have been developed and successfully integrated for Si-based monolithic microwave integrated circuit (MMIC) applications. Based on application requirements, the epitaxial layers for SiGe HBT's have been designed and optimized. A novel process technology is presented for the fabrication of multi-finger SiGe HBT's with fully self-aligned structure to reduce device parasitics. Extensive studies on the performance of SiGe HBT's DC, RF and power measurement results are employed to characterize the device for microwave integrated circuit designs. In additional to the development of microwave transistors, micromachining has been applied to lumped passive components. With a significant increase of the resonant frequency and the quality factor for the spiral inductors, the micromachined lumped passive components are used for MMIC implementations. Microwave couplers, multi-stage amplifiers, oscillators and power amplifiers using lumped components have been designed and implemented for X-band applications.