Investigation of yttrium oxide and silver/silver sulfide for memory resistive switching application

Abstract

The resistive switching (RS) phenomenon has attracted much interest for application in next generation non-volatile memory devices. Numerous metal chalcogenides and metal oxides have been found to exhibit this phenomenon. In this work, we investigate resistive switching in yttrium oxide (Y2O3) and silver/silver sulfide (Ag/Ag2S) materials, which show unipolar and bipolar RS behaviour respectively. We successfully demonstrate the RS hysteresis in both materials and found that the switching is independent of the electrode size, suggesting that the conductive path is filamentary in nature. The SET process in the Ag/Ag2S structure is not only induced by electric field, but is dependent on both the time duration and voltage magnitude when bias is applied. Y2O3 shows a superior ON/OFF resistance ratio of >1000000, good memory retention reliability performance, fast WRITE speed of ~10ns and small switching energy of the order of nanoJoules. These, coupled with the unipolar switching scheme and CMOS compatible fabrication process, makes Y2O3 a promising candidate material for application in resistive RAM.