Proton-Induced Upsets in SLC and MLC NAND Flash Memories

• Published in: IEEE transactions on nuclear science Vol. 60; no. 6; pp. 4130 - 4135
• Main Authors: Bagatin, Marta, Gerardin, Simone, Paccagnella, Alessandro, Ferlet-Cavrois, Veronique, Schwank, James R., Shaneyfelt, Marty R., Visconti, Angelo
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-12-2013; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Cross sections; Devices; Energy (nuclear); Energy distribution; Flash memories; Flash memory (computers); floating gate cells; Nonvolatile memory; Nuclear cross sections; Proton energy; Proton irradiation; Protons; Reliability; single event effect
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2013.2290033

We investigate proton-induced upsets in state-of-the-art NAND Flash memories, down to the 25-nm node. The most striking result is the opposite behavior of Multi-Level Cell (MLC) and Single-Level Cell (SLC) devices, in terms of floating gate error cross section as a function of proton energy. In fact, the cross section increases with proton energy in SLC whereas it decreases in MLC. The reason for this behavior is studied through comparison of heavy-ion data and device simulations. The main factors that determine proton energy dependence are discussed, such as the energy dependence of nuclear cross section between protons and chip materials, the LET, energy, and angular distributions of the generated secondaries, but also the heavy-ion and total dose response of the studied devices. Proton irradiation effects in the control circuitry of NAND Flash memories are shown as well.