Dry etching of all-oxide transparent thin film memory transistors

Transparent ferroelectric field-effect transistors of oxidic thin films have been fabricated, showing a memory effect with an on/off ratio of the channel conductance of more than three orders of magnitude. The devices consist of a 10 nm n-type SnO2:Sb semiconductor channel with a 10 nm BaZrO3 capping layer, In2O3:Sn contact pads, a 250 nm PbZr0.2Ti0.8O3 layer as a ferroelectric insulator, and conducting SrRuO3 as gate electrode. After deposition, the layers were structured by means of reactive ion etching. All materials were structured with a lithographically defined mask in a CHF3/Ar plasma. Etching with CHF3/Ar does not produce any volatile etch products but contrary to pure Ar sputter etching, no redeposited materials were found on the structures.