Engineering Commons^™

Very High Frequency Bipolar Junction Transistor Frequency Multiplier Drive Network Design And Analysis, Daniel Dale Schaeffer

Dissertations and Theses

The function of a frequency multiplier is verbatim -- a frequency multiplier is a circuit that takes a signal of particular frequency at the input and produces harmonic multiples of the input signal's frequency at the output. Their use is widespread throughout history, primarily in the application of frequency synthesis. When implemented as a part of a large system, a chain of multipliers can be used to synthesize multiple reference signals from a single high-performance reference oscillator.

Frequency multiplier designs use a variety of nonlinear devices and topologies to achieve excitation of harmonics. This thesis will focus on the design …

Accumulation Hole Layer In P-Gan/Algan Heterostructures, M. S. Shur, A. D. Bykhovski, R. Gaska, J. W. Yang, Grigory Simin, M. A. Khan

Grigory Simin

We present the results on piezoelectric and pyroelectricdoping in AlGaN-on-GaN and GaN-on-AlGaN heterostructures and demonstrate p-GaN/AlGaN structures with accumulation hole layer. Our results indicate that polarization charge can induce up to 5×10¹³ cm⁻² holes at the AlGaN/GaN heterointerfaces. We show that the transition from three-dimensional (3D) to two-dimensional (2D) hole gas can be only achieved for hole sheet densities on the order of 10¹³ cm⁻² or higher. At lower densities, only 3D-hole accumulation layer may exist. These results suggest that a piezoelectrically induced 2D-hole gas can be used for the reduction of the base spreading resistance …

Reliability Study Of Ingap/Gaas Heterojunction Bipolar Transistor Mmic Technology By Characterization, Modeling And Simulation, Xiang Liu

Electronic Theses and Dissertations

Recent years have shown real advances of microwave monolithic integrated circuits (MMICs) for millimeter-wave frequency systems, such as wireless communication, advanced imaging, remote sensing and automotive radar systems, as MMICs can provide the size, weight and performance required for these systems. Traditionally, GaAs pseudomorphic high electron mobility transistor (pHEMT) or InP based MMIC technology has dominated in millimeter-wave frequency applications because of their high fT and fmax as well as their superior noise performance. But these technologies are very expensive. Thus, for low cost and high performance applications, InGaP/GaAs heterojunction bipolar transistors (HBTs) are quickly becoming the preferred technology to …

Low-Voltage Bandgap Reference Design Utilizing Schottky Diodes, David L. Butler, R. Jacob Baker

Electrical and Computer Engineering Faculty Publications and Presentations

As semiconductor device geometries continue to shrink, the corresponding voltage applied across the processed devices must also be reduced. Therefore reference voltages used in integrated circuits will need to be reduced as well. A typical bandgap reference (BGR) voltage generator uses PN junction diodes or PNP BJT’s to bias the reference. The forward bias voltage of these devices is typically 0.7 volts, and has a limiting effect on how low a reference voltage can be generated, as well as how low a system voltage can be applied. Schottky, or metal-semiconductor (MS), diodes have a lower forward bias voltage, typically of …

Accumulation Hole Layer In P-Gan/Algan Heterostructures, M. S. Shur, A. D. Bykhovski, R. Gaska, J. W. Yang, Grigory Simin, M. A. Khan

Faculty Publications

We present the results on piezoelectric and pyroelectricdoping in AlGaN-on-GaN and GaN-on-AlGaN heterostructures and demonstrate p-GaN/AlGaN structures with accumulation hole layer. Our results indicate that polarization charge can induce up to 5×10¹³ cm⁻² holes at the AlGaN/GaN heterointerfaces. We show that the transition from three-dimensional (3D) to two-dimensional (2D) hole gas can be only achieved for hole sheet densities on the order of 10¹³ cm⁻² or higher. At lower densities, only 3D-hole accumulation layer may exist. These results suggest that a piezoelectrically induced 2D-hole gas can be used for the reduction of the base spreading resistance …

Nonlinearities In The Base Emitter Junction Of Heterojunction Bipolar Transistors, Oliver Woywode

Dissertations and Theses

The nonlinear behaviour of the base emitter junction in HBTs is investigated. Nonlinearities cause troublesome distortion and intermodulation of signals and raise the bit error rate. They are therefore a key issue in microwave communication systems. Hewlett-Packard's Microwave Design System (MDS) software package has been used to simulate these phenomena. The simulation results are verified by an analytical method called nonlinear current method which is a derivative of the Volterra series approach. With the aid of this method new analytical expressions are derived that provide insight into the subtleties of nonlinear phenomena. These expressions are evaluated by the program MAPLE …