超小型人工衛星搭載民生部品の放射線耐性に関する研究とその付加価値向上
宇宙機において、開発費を抑えるために民生部品を利用する動きが世界的にみられる。しかし、民生部品は宇宙環境で使用されることを想定していない。よって、それらの部品の宇宙実証をしなければならない。そこで、10cm 級の人工衛星「CubeSat」の利用が期待されている。
この論文では宇宙放射線環境について注目した。前述の通り民生部品は宇宙環境で使用されることを想定していないため、宇宙環境に特有である放射線による不具合を引き起こし、人工衛星が機能停止に陥る可能性がある。特に、宇宙放射線に起因するトータルドーズ効果という現象は半導体の特性を累積的に変化させ、要求される動作をしなくなる可能性がある。本研究においては MOSFET をはじめとする半導体スイッチング素子に放射線を照射し特性の変化を見た。
結果として、放射線の影響が大きい素子と小さい素子を判別することが出来た。それらの情報を「超小型衛星搭載民生部品データベース」に公開することで、今後の衛星づくりにおける部品選定に役立てると考える。

Improvement of the value of commercial components by improving
radiation test
In spacecraft, there are global movements that use Commercial-Off-The-Shelf (COTS) components to reduce
development costs. However, COTS components are not intended for use in space environments. Therefore,
these components need to be verified to work in space environment. Regarding the verification, it is expected
to use the 10cm class satellite "CubeSat".
This paper focuses on radiation environment in space. As mentioned above, COTS components are not supposed
to be used in the space environment, so some problems may occur due to radiation specific to space environment,
and satellite may not function as expected. In particular, the phenomenon of total ionizing dose (TID) effectcaused by cosmic radiation can cumulatively change the characteristics of semiconductors and prevent them fromperforming as required. In this paper, we irradiated semiconductor switching devices such as MOSFETs andobserved the changes in their characteristics.

As a result, we were able to determine which devices were affected by radiation and which were not.
This information will be made available to the public in the "Database of Nano Satellite Components"(https://space-cots-data.jp/) and will be useful in selecting components for future satellite development.

目次
第 1 章 序論 ......................................................................................................................................31.1 研究背景 .................................................................................................................................31.2 宇宙放射線環境......................................................................................................................51.2.1 放射線 .................................................................................................................................5
1.2.2 宇宙放射線環境...............................................................................................................7
1.3 超小型衛星搭載民生部品データベース ..............................................................................81.5 研究目的 .................................................................................................................................9
第 2 章 放射線による影響.............................................................................................................102.1 放射線が半導体に及ぼす影響............................................................................................102.1.1 Total Ionizing Dose Effect ..............................................................................................102.1.2 Single Event Effect .........................................................................................................14第 3 章 放射線試験 ........................................................................................................................18
3.1 TID 試験概要 ........................................................................................................................183.2 試験施設 ...............................................................................................................................183.2.2 産業医科大学アイソトープ研究センター .................................................................213.3 試験システム .......................................................................................................................243.3.1 概要 ................................................................................................................................243.3.2 データ取得方法.............................................................................................................25
3.3.3 評価ボード.....................................................................................................................27
第 4 章 TID 試験の実施 .................................................................................................................28
4.1 本研究の TID 試験の目的 ...................................................................................................28
4.2 素子の選定 ...........................................................................................................................28
4.3 試験基板の作製....................................................................................................................30
4.4 TID 試験の実施 ....................................................................................................................32
4.5TID 試験方法 ......................................................................................................................32

4.6 結果 .......................................................................................................................................33
4.6.1 UMD5NTR .....................................................................................................................33
4.6.2 DTC144EKAT146 ..........................................................................................................35
4.6.3 PDTA144EU ...................................................................................................................36
4.6.4 MUN5114DW1T1G .......................................................................................................36
4.6.5 2SK1062 .........................................................................................................................37
4.6.6 SI7106DN-T1-E3 ............................................................................................................384.6.7 SI7228DN-T1-GE3 .........................................................................................................39
4.6.8 SQA403EJ-T1_GE3 .......................................................................................................40
4.6.9 SSM3J120TU(TE85L) ....................................................................................................401

4.6.10

SSM3K123TU,LF .......................................................................................................41

4.6.11 FDB8441 .......................................................................................................................41
4.6.12 SSM6K411TU(TE85L,F...............................................................................................42
4.7 考察 .......................................................................................................................................424.7.1 個体差が生じた理由.....................................................................................................424.7.2 突入電流 ........................................................................................................................424.7.3 変化率 ............................................................................................................................43
4.7.4 前回の試験との変化率の比較.....................................................................................45
4.7.5 MOSFET 以外のトランジスタで劣化が見られた理由 ............................................46
4.7.6

I-V 特性 ..........................................................................................................................47

第 5 章 結論 ....................................................................................................................................55
第 6 章 今後の予定と課題.............................................................................................................56
6.1 TID 試験の今後 ....................................................................................................................56
6.2 SEL 試験の今後 ...................................................................................................................56
謝辞 ....................................................................................................................................................57
参考文献 ............................................................................................................................................58

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