Large memory effect in oxidic thin-film transistors with a ferroelectric insulator

We have fabricated ferroelectric field-effect transistors of oxidic thin films, showing a memory effect with an on/off ratio of more than three orders of magnitude. The devices consist of a n-type SnO/sub 2/ semiconductor channel, a PbZr/sub 0.2/Ti/sub 0.8/O/sub 3/ layer as a ferroelectric insulator, and conducting SrRuO/sub 3/ as the gate electrode. The results demonstrate for the first time that an all-thin-film ferroelectric transistor-where the semiconductor as well as the ferroelectric insulator are deposited as thin films-can exhibit a memory effect of many orders of magnitude.