Uncovering the fundamental driver of semiconductor radiation tolerance
Radiation damage is a prominent cause of device failure in orbit, but we do not currently understand what innate property allows some semiconductors to sustain little damage while others accumulate defects rapidly with dose. These devices include circuits required for control and communication as we...
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Published: |
Massachusetts Institute of Technology
2022
|
| Online Access: | https://hdl.handle.net/1721.1/140182 https://orcid.org/0000-0001-9787-5249 |
| _version_ | 1811087523124871168 |
|---|---|
| author | Logan, Julie V. |
| author2 | Short, Michael P. |
| author_facet | Short, Michael P. Logan, Julie V. |
| author_sort | Logan, Julie V. |
| collection | MIT |
| description | Radiation damage is a prominent cause of device failure in orbit, but we do not currently understand what innate property allows some semiconductors to sustain little damage while others accumulate defects rapidly with dose. These devices include circuits required for control and communication as well as instruments used for observation. This disables the ability to design materials with radiation tolerance as a criterion. The first contribution of this thesis is to improve our understanding of semiconductor damage done in orbit by showing that (1) nuclear transmutation is an insignificant damage mechanism for any prominent satellite orbit and common optoelectronic material and (2) current dominant terrestrial radiation-tolerance qualification tests (high energy protons) are unrepresentative of the damage done in orbit (recommendations are given to improve their realism). To address the main problem of determining the driver of semiconductor radiation tolerance, the first step is to generate a dataset of the relative radiation tolerance of a large range of semiconductors (exposed to the same radiation damage and characterized in the same way). This was accomplished through the development of positron annihilation lifetime spectroscopy (PALS) and Rutherford backscatter channeling (RBS/C) experiments to compare the relative open volume and displaced lattice atom buildup in InAs, InP, GaP, GaN, ZnO, MgO, and Si as a function of radiation damage. With this experimental information on relative radiation tolerance in hand, hybrid density functional theory (DFT) electron densities (and their derived quantities) are processed by considering their gradient and laplacian to obtain key fundamental information about the interactions in each material. It is shown that simple, undifferentiated values (which are typically used to describe bond strength) are insufficient to predict radiation tolerance. Instead, the curvature of the electron density at bond critical points provides a measure of radiation tolerance consistent with the experimental results obtained. This curvature and associated forces surrounding bond critical points disfavors localization of displaced lattice atoms at these points, favoring their diffusion toward perfect lattice positions. Previous theories for the driver of radiation tolerance, like bond strength, ionicity, and bandgap, are shown to be inconsistent with the experimental results. With this criterion to predict radiation tolerance, simple DFT simulations can be conducted on potential new materials to predict their anticipated operation in the demanding space radiation environment. |
| first_indexed | 2024-09-23T13:47:27Z |
| format | Thesis |
| id | mit-1721.1/140182 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T13:47:27Z |
| publishDate | 2022 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/1401822022-02-08T03:29:41Z Uncovering the fundamental driver of semiconductor radiation tolerance Logan, Julie V. Short, Michael P. Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Radiation damage is a prominent cause of device failure in orbit, but we do not currently understand what innate property allows some semiconductors to sustain little damage while others accumulate defects rapidly with dose. These devices include circuits required for control and communication as well as instruments used for observation. This disables the ability to design materials with radiation tolerance as a criterion. The first contribution of this thesis is to improve our understanding of semiconductor damage done in orbit by showing that (1) nuclear transmutation is an insignificant damage mechanism for any prominent satellite orbit and common optoelectronic material and (2) current dominant terrestrial radiation-tolerance qualification tests (high energy protons) are unrepresentative of the damage done in orbit (recommendations are given to improve their realism). To address the main problem of determining the driver of semiconductor radiation tolerance, the first step is to generate a dataset of the relative radiation tolerance of a large range of semiconductors (exposed to the same radiation damage and characterized in the same way). This was accomplished through the development of positron annihilation lifetime spectroscopy (PALS) and Rutherford backscatter channeling (RBS/C) experiments to compare the relative open volume and displaced lattice atom buildup in InAs, InP, GaP, GaN, ZnO, MgO, and Si as a function of radiation damage. With this experimental information on relative radiation tolerance in hand, hybrid density functional theory (DFT) electron densities (and their derived quantities) are processed by considering their gradient and laplacian to obtain key fundamental information about the interactions in each material. It is shown that simple, undifferentiated values (which are typically used to describe bond strength) are insufficient to predict radiation tolerance. Instead, the curvature of the electron density at bond critical points provides a measure of radiation tolerance consistent with the experimental results obtained. This curvature and associated forces surrounding bond critical points disfavors localization of displaced lattice atoms at these points, favoring their diffusion toward perfect lattice positions. Previous theories for the driver of radiation tolerance, like bond strength, ionicity, and bandgap, are shown to be inconsistent with the experimental results. With this criterion to predict radiation tolerance, simple DFT simulations can be conducted on potential new materials to predict their anticipated operation in the demanding space radiation environment. Ph.D. 2022-02-07T15:28:56Z 2022-02-07T15:28:56Z 2021-09 2021-10-08T14:42:15.190Z Thesis https://hdl.handle.net/1721.1/140182 https://orcid.org/0000-0001-9787-5249 In Copyright - Educational Use Permitted Copyright MIT http://rightsstatements.org/page/InC-EDU/1.0/ application/pdf Massachusetts Institute of Technology |
| spellingShingle | Logan, Julie V. Uncovering the fundamental driver of semiconductor radiation tolerance |
| title | Uncovering the fundamental driver of semiconductor radiation tolerance |
| title_full | Uncovering the fundamental driver of semiconductor radiation tolerance |
| title_fullStr | Uncovering the fundamental driver of semiconductor radiation tolerance |
| title_full_unstemmed | Uncovering the fundamental driver of semiconductor radiation tolerance |
| title_short | Uncovering the fundamental driver of semiconductor radiation tolerance |
| title_sort | uncovering the fundamental driver of semiconductor radiation tolerance |
| url | https://hdl.handle.net/1721.1/140182 https://orcid.org/0000-0001-9787-5249 |
| work_keys_str_mv | AT loganjuliev uncoveringthefundamentaldriverofsemiconductorradiationtolerance |