Random telegraph noise-based analysis of electron traps of sub-30-nm DRAM cell-array transistors in cryogenic operation

The electron-traps parameters of the fin-type buried-channel-array transistor (BCAT) in a dynamic random-access memory (DRAM) cell is investigated with a random-telegraph-noise (RTN)-based analysis at various temperatures including 77 K. RTN fluctuation caused by the e^--trapping is reduced with decreasing thermal energy. The extraction results exhibit similar values between 230∼370 K, but at 77 K, a singularity point is observed, indicating the necessity for analysis to enhance the retention of DRAM operating at cryogenic temperatures. In order to validate the accuracy of the RTN-based trap parameters extracted through analysis, TCAD simulations are conducted for the off current (I_off) under Fowler-Nordheim (FN) stress. These findings provide valuable insights for investigating the reliability and the leakage of DRAM in cryogenic environment, particularly for applications in quantum computing.