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Title: | The characterization of aluminum gallium arsenide resonant tunneling diodes at microwave frequencies |
Author(s): | Gering, Joseph Michael |
Doctoral Committee Chair(s): | Coleman, Paul D. |
Department / Program: | Electrical and Computer Engineering |
Discipline: | Electrical Engineering |
Degree Granting Institution: | University of Illinois at Urbana-Champaign |
Degree: | Ph.D. |
Genre: | Dissertation |
Subject(s): | Engineering, Electronics and Electrical |
Abstract: | Double-barrier, single-quantum-well, resonant tunneling diodes employing variable thickness Al$\sb{0.25}$Ga$\sb{0.75}$As barriers and 5 nm GaAs wells have been studied. Low doped GaAs buffer regions ($N\sb D$ $\approx$ 5 $\times$ 10$\sp{16}$ cm$\sp{-3}$) were placed next to the barriers to reduce the device capacitance and to prevent dopant migration into the barriers. The diodes were mounted in a coplanar waveguide test circuit that was placed in a microwave test fixture employing Wiltron K Connector spark plug launchers to transition from the coplanar waveguide to coax. Small-signal reflection coefficient measurements were made on these diodes. The measurements were de-embedded using a two-tiered error correction scheme composed of the line-reflect-match and thru-reflect-line techniques. A small-signal equivalent circuit model consisting of a resistor, $R\sb S$, in series with the parallel combination of a nonlinear conductance, G, and a capacitance, C, was used. The series resistance and shunt capacitance were found to be independent of bias voltage while the conductance was found to be related to the dc current-voltage characteristic $\lbrack I(V)\rbrack$ of the diode by$$G = {{dI\over dV}\over{1-{dI\over dV}R\sb S}}.$$ The large-signal behavior of the diode was investigated. The small-signal equivalent circuit model for the diode was used for the large-signal analysis by replacing the nonlinear conductance with an ac conductance, $G\sb{\rm ac}$ = $I\sb1$/$V\sb1$, where $v(t)$ = $V\sb B$ + $V\sb1$ cos $\omega t$ is the instantaneous voltage across the conductance with $V\sb B$ being the bias voltage and where $i(t)$ = $I\sb0$ + $I\sb1$ cos $\omega t$ + $I\sb2$ cos 2$\omega t$ + $\cdots$ is the Fourier series representation of the instantaneous current through the conductance as calculated from the current-voltage curve that has been corrected for the series resistance, $R\sb S$. The effects of higher harmonic voltage terms was found to be negligible. The diode was studied as a microwave detector. When biased at the peak in the current-voltage curve, the diode provides a novel, full-wave rectification of a superimposed ac signal. The diode's performance as a detector is comparable to Schottky point contact detectors at low frequencies, while the resonant tunneling diode's performance degrades at higher frequencies because of its intrinsic parasitics. |
Issue Date: | 1991 |
Type: | Text |
Language: | English |
URI: | http://hdl.handle.net/2142/22268 |
Rights Information: | Copyright 1991 Gering, Joseph Michael |
Date Available in IDEALS: | 2011-05-07 |
Identifier in Online Catalog: | AAI9136598 |
OCLC Identifier: | (UMI)AAI9136598 |
This item appears in the following Collection(s)
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Dissertations and Theses - Electrical and Computer Engineering
Dissertations and Theses in Electrical and Computer Engineering -
Graduate Dissertations and Theses at Illinois
Graduate Theses and Dissertations at Illinois