Impact of Displacement Defect Owing to Cosmic Rays on Three-Nanometer-Node Nanosheet FET 6T Static Random Access Memory

Abstract

In this work, the effect of displacement defect (DD) owing to cosmic rays on six-transistor (6T) static random access memory (SRAM) with a 3 nm node nanosheet field-effect transistor (NSFET) is investigated using technology computer-aided design (TCAD) simulation. In order to comprehensively study the uncertainty of the radiation of NSFET 6T SRAM, the shape of the DD cluster cross-section and the transistor damaged by the DD in 6T SRAM are considered. Read static noise margin (RSNM) degradation (19 %) is the highest when the rectangular cross-section of the DD cluster (rectangular-DD cluster) is located in the pull-down1 (PD1) transistor. To mitigate the rectangular-DD cluster damage, we studied the variation in the DD cluster influence on the sheet shape and the source/drain (S/D) overlap length fluctuation. The sheet shape resulted in 2.3 % lower RSNM degradation in NS compared with nanowire (NW). Under the worst conditions (PD1 transistor damaged rectangular-DD cluster, NW structure), the S/D underlap structure showed 3.7 % lower RSNM degradation than the S/D overlap structure.

Keywords

• Displacement defect (DD)
• radiation effects
• reliability
• nanosheet FET (NSFET)
• static random access memory (SRAM)
• technology computer-aided design simulation (TCAD)