Reduced HfO2 Resistive Memory Variability by Inserting a Thin SnO2 as Oxygen Stopping Layer

One of the major roadblocks for filamentary type resistive random access memory is variations in both the write voltage and the read resistance. The variation is inevitable because of the stochastic nature of oxygen ion movement inside the metal oxide. In this letter, we show that by inserting a thin SnO2 layer within the HfO2 switching layer, these variations can be significantly reduced. The TiN/HfO2/SnO2/HfO2/Pt material stack achieves similar to 10 times smaller standard deviation for the high resistance state(>100k Omega) cycle to cycle distribution compared with the control group without the SnO2 layer. The tight high resistance state distribution retained after 10(7) pulse cycling. Incremental RESET pulse measurement indicates that the thin SnO2 acts as an oxygen stopping layer and thus explains the origin of reduced variability. The concept of an oxygen stopping layer is promising for reducing variability for resistive memory.

Automated summary

The insertion of a thin SnO2 layer within the HfO2 switching layer significantly reduces variations in write voltage and read resistance for resistive random access memory. This approach improves the performance and stability of the memory device by decreasing cycle-to-cycle differences and retaining a tight resistance distribution after a large number of pulse cycles. The thin SnO2 acts as an oxygen stopping layer, explaining the origin of reduced variability and showing promise for reducing variability in resistive memory technology.