A ferroelectric semiconductor field-effect transistor

Ferroelectric field-effect transistors employ a ferroelectric material as a gate insulator, the polarization state of which can be detected using the channel conductance of the device. As a result, the devices are potentially of use in non-volatile memory technology, but they suffer from short retention times, which limits their wider application. Here, we report a ferroelectric semiconductor field-effect transistor in which a two-dimensional ferroelectric semiconductor, indium selenide (α-In₂Se₃), is used as the channel material in the device. α-In₂Se₃ was chosen due to its appropriate bandgap, room-temperature ferroelectricity, ability to maintain ferroelectricity down to a few atomic layers and its potential for large-area growth. A passivation method based on the atomic layer deposition of aluminium oxide (Al₂O₃) was developed to protect and enhance the performance of the transistors. With 15-nm-thick hafnium oxide (HfO₂) as a scaled gate dielectric, the resulting devices offer high performance with a large memory window, a high on/off ratio of over 10⁸, a maximum on current of 862 μA μm⁻¹ and a low supply voltage.