The Effect of Energy Loss Straggling on SEUs Induced by Low-Energy Protons in 28 nm FDSOI SRAMs

• Main Authors: Lujie Zhang, Jingyan Xu, Yaqing Chi, Yang Guo
• Format: Article
• Language: English
• Published: MDPI AG 2019-08-01
• Series: Applied Sciences
• Subjects: energy loss straggling; low-energy proton; single event upset; sensitive volume; fully-depleted silicon on insulator; linear energy transfer
• Online Access: https://www.mdpi.com/2076-3417/9/17/3475

Sensitive volume thickness for silicon on insulator (SOI) devices has scaled to the point that energy loss straggling cannot be ignored within the development of the manufacturing process. In this study, irradiation experiments and Geant4 simulation were carried out to explore the influence of energy loss straggling on single event upsets (SEUs) caused by sub-8 MeV proton direct ionization. We took a 28 nm fully-depleted SOI static random-access memory (SRAM) as the research target. According to our results, the depositing energy spectrum formed by monoenergetic low-energy protons that penetrated through the sensitive volume of the target SRAM was extremely broadened. We concluded that the SEUs we observed in this article were attributed to energy loss straggling. Therefore, it is sensible to take the new mechanism into consideration when predicting proton-induced SEUs for modern nanometer SOI circuits, instead of the traditional linear energy transfer (LET) method.