Design and implementation of a high-flux photoneutron converter for analysis of fast neutron radiation damage on gallium nitride transistors
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Authors
Westrick, Connor
Subjects
Fast neutrons
non-ionizing radiation
gallium nitride
high electron mobility transistors
flux
fluence
radiation
linear accelerator
non-ionizing radiation
gallium nitride
high electron mobility transistors
flux
fluence
radiation
linear accelerator
Advisors
Weatherford, Todd
Harmon, Frank
Date of Issue
2017-06
Date
Jun-17
Publisher
Monterey, California: Naval Postgraduate School
Language
Abstract
Gallium Nitride(GaN) is known for its wide-energy bandgap of 3.4 eV and its high-efficiency as a semiconductor, which makes it a prime material for high-power, high-frequency, and low-noise systems. Specifically, GaN high electron-mobility transistors (HEMTs) have seen an increase in popularity due to its two-dimensional electron gas (2DEG) that allows for increased mobility of un-doped GaN. In this work, GaN HEMTs were irradiated with a fluence of 2x1016n cm2 while maintaining a 99 percent fast-to-thermal neutron ratio. There were three phases to this work, the first was the design and fabrication of a photoneutron converter. The second was the design and implementation of a device testing suite in order to characterize the GaN HEMTs before, during, and after the experiment. The last was the analysis of the data showing the relationship of the electrical and physical characteristics of the devices with respect to the fast neutron fluence. The damage was also analyzed using a total displacement calculation for each layer of the device. The GaN HEMTs linearly degraded due to the high energy neutron displacements within the heterojunction layers.
Type
Thesis
Description
Series/Report No
Department
Electrical and Computer Engineering (ECE)
Organization
Identifiers
NPS Report Number
Sponsors
Funder
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Citation
Distribution Statement
Approved for public release; distribution is unlimited.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.