Total Ionizing Dose Effect of CNTFETs and SRAM Cells With Different Bias Conditions

Carbon nanotube (CNT)-based devices and circuits exhibit inherent radiation tolerance, making them promising candidates for harsh environment applications. Examining device characteristics under bias conditions is essential for practical applications. This work investigates total ionizing dose (TID) effects on CNTFET and SRAM performance under various bias conditions. Both transistor I<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">DS</sub>-V<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">GS</sub> characteristics and SRAM static noise margin (SNM) are evaluated. Experimental results reveal that CNTFET threshold voltage (V<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub>) shifts strongly depend on irradiation bias conditions. SNM degradation is more severe under biased conditions than under floating conditions. The V<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sub> shifts result from the synergistic effects of bias stress and irradiation, with interface traps and oxide trapped charges in the passivation layer playing dominant roles. Different bias conditions cause varying degrees of transistor degradation within SRAM cells, resulting in SNM variations. Optimizing passivation processes is crucial for mitigating interface traps formation and enhancing device reliability under irradiation, thereby advancing carbon-based circuit applications.