Abstract
Ovonic threshold switching (OTS) materials that are frequently used with a resistor (1S1R) in memory devices have been found to show controllable and reversible memory properties, which could enable new memory architectures. Here, we examine the impact of composition on the polarity-dependent memory properties of GexSe1-x OTS materials and reveal that an increase in Se content results in a higher set voltage threshold (Vth), a lower reset current (IRST), and a higher set energy. Specifically, Ge56Se44 demonstrates two distinct Vth of 5.1 and 3.8 V, which retain after annealing at 85 ℃ for one day. We fabricated Ge56Se44 into 1000 by 1000 cross-point pillar arrays and tested 100 of them. The results demonstrated that these Ge56Se44 devices show similar memory properties with a reset speed of 1 μs, a set speed of 50 ns, and an endurance of over 105 cycles. Interestingly, the Ge56Se44 pillars' reset and set states could be attributed to polarized atomic distributions. By utilizing GexSe1-x, we demonstrate a true cross-point switch-only-memory technology and provide mechanistic insights for self-selecting OTS materials.