Ferroelectric FET with Gd-doped HfO2: A Step Towards Better Uniformity and Improved Memory Performance

Abstract

In this work we present the optimization process of Gadolinium doped hafnium oxide (Gd:HfO2) for ferroelectric FET (FEFET). The ferroelectricity of Gd:HfO2 in Metal/Ferroelectric/Insulator/Semiconductor (MFIS) stack has been verified by polarization measurements in ferroelectric capacitors (FECAP). The memory window (MW) was further investigated in FEFETs where processing parameters, such as Gd concentration and the gate metal stack, have been tuned to improve the performance. Gd doping enables a maximal MW of 1.6V, with endurance up to 10(5) cycles. Variability of fabricated devices was also compared to Si:HfO2 FEFET, with the former showing tighter distribution of the main electrical parameters.