Graduate Exam Abstract
Abishek Stephen Vellankanni
M.S. Final
May 14, 2026, 10:00 am - 12:00 pm
C101B
Aging-Induced Data Imprinting in SRAM Arrays: Characterization, Analysis, and Mitigation
Abstract: Static random-access memory (SRAM) power-up states are widely used as a source of randomness and device uniqueness, but they can also retain traces of previously stored information after prolonged stress, creating an end-of-life security vulnerability. This thesis investigates both the formation of aging-induced data imprinting in commercial off-the-shelf (COTS) SRAMs and the mitigation of such imprints through radiation-based sanitization. Under accelerated thermal aging, multiple SRAM chips from different vendors and technology nodes exhibit reverse imprinting, in which the post-aging power-up state becomes biased toward the complement of the stored data pattern. The imprint strength depends on aging temperature, stress duration, and supply voltage, while relaxation measurements show that the induced patterns can remain visible for months at room temperature. The observed behavior indicates that negative bias temperature instability (NBTI)-induced threshold-voltage shifts in PMOS transistors are the dominant mechanism responsible for the effect. To mitigate this vulnerability, this thesis further demonstrates a total ionizing dose (TID)-based sanitization technique for aged SRAM arrays. Experimental results show near-complete sanitization at approximately 50-100 krad(Si) for most of the aged chips. Overall, this thesis highlights both the security risk posed by aging-induced SRAM data imprinting and the effectiveness of radiation-based sanitization as a practical end-of-life mitigation approach.
Adviser: Dr. Biswajit Ray
Co-Adviser: NA
Non-ECE Member: Dr. Sudeep Pasricha
Member 3: Dr. Indrajit Ray
Addional Members: NA
Publications:
1. U. Surendranathan, A. S. Vellankanni, A. Milenkovic, U. Guin and B. Ray, "Ionizing Radiation-Induced Data Imprinting Effects in SRAM Arrays," in IEEE Transactions on Nuclear Science, vol. 72, no. 4, pp. 1252-1258, April 2025, doi: 10.1109/TNS.2025.3543233.
2. A. S. Vellankanni et al., "Real-Time Radiation Dosimeter Using SRAM Power-Up State," 2024 24th European Conference on Radiation and Its Effects on Components and Systems (RADECS), Maspalomas, Spain, 2024, pp. 1-7, doi: 10.1109/RADECS61970.2024.11298580.
In Review:
3. A. S. Vellankanni et al., "Aging-Induced Data Imprinting Effects on SRAM Array," in the ISVLSI 2026 conference.
4. A. S. Vellankanni et al., "Data Sanitization of Aged SRAM Array using Ionizing Radiation," in the NSREC 2026 conference.
Program of Study:
ECE528
ECE554
ECE 580C6
ERHS530
CS440
CS556
CS501
ECE799
