Ferroelectric HfO${}_2$ Memory Transistors with High-$\kappa$ Interfacial Layer and Write Endurance Exceeding $10^{10}$ Cycles

Abstract

We demonstrate ferroelectric (FE) memory transistors on a crystalline silicon channel with endurance exceeding $10^{10}$ cycles. The ferroelectric transistors (FeFETs) incorporate a high-$\kappa$ interfacial layer (IL) of thermally grown silicon nitride (SiN${}_x$) and a thin 4.5 nm layer of Zr-doped FE-HfO${}_2$ on a $\sim$30 nm SOI channel. The device shows a $\sim$ 1V memory window in a DC sweep of just $\pm$ 2.5V, and can be programmed and erased with voltage pulses of $V_G=\pm$ 3V at a pulse width of 250 ns. The device also shows very good retention behavior. These results indicate that appropriate engineering of the IL layer could substantially improve FeFET device performance and reliability.