Effect of Indium Doping on the Reliability Characteristics of Chalcogenide GeSbSeTe Thin-Film-Based Selector-Only Memory Devices

Next-generation memory technologies demand fast speed, high density, and low power to enhance data processing and storage. Storage class memory (SCM) has emerged as a promising solution, combining DRAM-like latency with the non-volatility and cost efficiency of NAND flash. Among various candidates, selector-only memory (SOM) is particularly attractive for a 3D crossbar array (CA), as it distinguishes data states via bias-polarity-induced threshold voltage (<i>V</i>_th) modulation without the need for separate memory elements. In this study, the influence of indium (In) doping on GeSbSeTe-based SOM devices was systematically investigated. Increasing the In concentration from 2% (In-poor) to 6% (In-rich) expanded the memory margin (Δ<i>V</i>_th) from 0.7 to 1.8 V and significantly improved data retention, maintaining a stable state for 2 h at 85 °C. Conversely, under a 100 ns programming pulse, the In-rich device exhibited a rapid degradation of Δ<i>V</i>_th from 1.5 to 0.04 V, while the In-poor device maintained a wider margin of 0.2 V under the same condition, indicating faster switching but reduced stability. These results demonstrate a clear trade-off between operation speed and retention, highlighting the critical role of trap-state modulation in determining device performance. The findings provide valuable insight into switching mechanisms and design guidelines.