Angular Dependency of Neutron-Induced Multiple Cell Upsets in 65-nm 10T Subthreshold SRAM

作者：Harada Ryo^*; Abe Shin Ichiro; Fuketa Hiroshi; Uemura Taiki; Hashimoto Masanori; Watanabe Yukinobu

来源：IEEE Transactions on Nuclear Science, 2012, 59(6): 2791-2795.

DOI：10.1109/TNS.2012.2224373

• Angular dependency
• multiple cell upset
• neutron-induced soft error
• PHITS (particle and heavy ion transport code system)
• subthreshold circuit

This paper reports neutron-induced MCU (Multiple Cell Upset) measured in 0.4-V 65-nm 10T SRAM at two incident angles of 0 degrees and 60 degrees. The measurement results show that the ratio of the number of measured MCUs at the angles of 60 degrees to that at 0 degrees is 1.13 in 0.4-V operation, while the ratio of neutrons radiated to the test chip was 50% at 60 degrees. The spatial MCU patterns measured at 60 degrees indicate that forward emission of secondary ions plays an important role to cause the angular dependency in 0.4-V operation. Furthermore, a Monte-Carlo simulation using PHITS (Particle and Heavy Ion Transport code System) was performed to confirm the measured angular dependency of neutron-induced MCUs. The simulation results show that the ratio of the number of MCUs at the angles of 60 degrees to that at 0 degrees is 1.20 and the same tendency of MCU patterns is observed. The measured angular dependency of neutron-induced MCUs is mostly reproduced by the simulated generation and transport of secondary ions.

• 出版日期2012-12