Ferroelectric‐HfO2 Transistor Memory with IGZO Channels

Summary

We have proposed, designed, and experimentally demonstrated ultrathin InGaZnO (IGZO) channel ferroelectric‐HfO₂ field‐effect transistors (FETs) with memory operation toward 3D vertical‐stack ferroelectric FETs (FeFETs). The design guideline of IGZO FeFETs is provided by simulation. The physical and electrical properties of metal–HfZrO₂(HZO)–IGZO–metal capacitors are experimentally investigated. IGZO helps ferroelectric‐phase formation of HZO, and the capacitor shows clear ferroelectricity with high reliability. Ultrathin‐body IGZO FeFETs show high mobility, a nearly ideal subthreshold slope, and controllable memory characteristics with 8 nm channel thickness in experiments, thanks to the properties of IGZO, junctionless FET operation, and a nearly zero low‐k interfacial layer with low interface state density.