Date of Award

2024

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Electrical and Computer Engineering

Committee Chair

Aleksandar Milenkovic

Committee Member

Laurie Joiner

Committee Member

Timothy Boykin

Committee Member

Aubrey Beal

Research Advisor

Biswajit Ray

Subject(s)

Flash memories (Computers)-Effect of radiation on, Static random access memory--Effect of radiation on

Abstract

Radiation effects in semiconductor devices have gained great traction in recent years due to an exponential growth in space exploration. The harsh conditions of space, devoid of the atmosphere and Earth's magnetic field, pose considerable challenges to electronic systems due to ionizing radiation exposure. While radiation-hardened (rad-hard) components are continually under development, they often lag several technology generations compared to commercial off-the-shelf (COTS) parts. Notably, rad-hard memories, particularly in terms of capacity (megabytes vs. terabytes) and cost, fall short compared to regular COTS memories. This underscores the compelling need to evaluate the radiation tolerance of COTS memories. This dissertation focuses on ionizing radiation effects on NAND flash and Static Random Access Memory (SRAM). We explore the total-ionizing-dose (TID) effects on 3D NAND by studying the bit error pattern with TID. We find that electrical noise contributes to a significant percentage of bit-errors and that radiation causes noise to increase during memory read operation. We present a powerful mitigation strategy to counteract radiation-induced noise increase by pre-programming factory-erase memory blocks before deployment. Furthermore, we investigate TID effects on the power-up characteristics of COTS-SRAM memories. The SRAM power-up state, serving as a unique digital fingerprint or physical unclonable function (PUF) for device authentication, undergoes significant alterations due to ionizing radiation exposure. This may lead to authentication failures in the space and other harsh environment. To protect SRAM PUF from ionizing radiation, we propose a robust mitigation strategy involving the storage of an appropriate data pattern during irradiation. Lastly, we explore ionizing radiation as a potential attack vector posing a significant security threat to SRAM-based computing systems. Our research uncovers data imprinting effects caused by ionizing radiation, which could be exploited by adversaries for data leakage. Additionally, ionizing radiation induces a substantial reduction in SRAM data remanence time, and we present this as a mitigation strategy against security attacks relying on SRAM data remanence.

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