Impact of variations of threshold voltage and hold voltage of threshold switching selectors in 1S1R crossbar array**Project supported by the MOST of China (Grant No. 2016YFA0201801), the Beijing Advanced Innovation Center for Future Chip (ICFC), Beijing Municipal Science and Technology Project (Grant No. D161100001716002), and the National Natural Science Foundation of China (Grant Nos. 61674089, 61674087, 61674092, 61076115, and 61774012),

Abstract

The impact of the variations of threshold voltage (Vth) and hold voltage (Vhold) of threshold switching (TS) selector in 1S1R crossbar array is investigated. Based on ON/OFF state I–V curves measurements from a large number of Ag-filament TS selectors, Vth and Vhold are extracted and their variations distribution expressions are obtained, which are then employed to evaluate the impact on read process and write process in 32 × 32 1S1R crossbar array under different bias schemes. The results indicate that Vth and Vhold variations of TS selector can lead to degradation of 1S1R array performance parameters, such as minimum read/write voltage, bit error rate (BER), and power consumption. For the read process, a small Vhold variation not only results in the minimum read voltage increasing but it also leads to serious degradation of BER. As the standard deviation of Vhold and Vth increases, the BER and the power consumption of 1S1R crossbar array under 1/2 bias, 1/3 bias, and floating scheme degrade, and the case under 1/2 bias tends to be more serious compared with other two schemes. For the write process, the minimum write voltage also increases with the variation of Vhold from small to large value. A slight increase of Vth standard deviation not only decreases write power efficiency markedly but also increases write power consumption. These results have reference significance to understand the voltage variation impacts and design of selector properly.