Process maturity: Stable SnOx can behave as either n-type or p-type semiconductor depending on the defect type and density. It can be used for both RRAM and TFTs, therefore, it is a suitable material for CMOS integration and for all oxide 1T1R devices. The prepared SnOx-based RRAM devices show analog switching and either non-volatile or volatile behaviour depending on the electrode materials.

Process maturity: Stable The device is formingless and has low voltage operation. Similar behaviour can be found with devices made with thinner ZnO layer (>30 nm); however, the On/Off ratio is smaller. Thinner devices exhibit volatile characteristics. Nevertheless, the device yield needs to be improved.

Process maturity: Stable D1 having small size cell (SA5) exhibits stable switching. However, the instability exhibited in larger cell (SA60) can be avoided by introducing Cr barrier layer (D2).

Process maturity: Stable This is a variation of the TiOx standard recipe aimed to address volatility issues to otherwise non-volatile devices. It is realised as a thin AlOx layer introduced between the active layer and top electrode. The layer is thin enough as to amount as an interfacial modification rather that true bilayer devices. Devices exhibit lower volatility which eventually results in satisfactory multi-bit performance.

Process maturity: Stable TiOx-based memristors are the basic devices fabricated by our lab and have been used for many different papers and applications. They provide reliable non-volatile or volatile behaviour depending on the choice of electrodes and forming procedure. Depending on forming method volatile behaviour is still present even in formed devices. Items with (*) below indicate possibility for CMOS integration.