Modulation of Oxygen Content and Ferroelectricity in Sputtered Hafnia‐Zirconia by Engineering of Tungsten Oxide Bottom Electrodes
Xuetao Wang, Stefan Slesazeck, Thomas Mikolajick, Matthias Grube
Abstract
Abstract The well‐developed high‐k technologies ease the integration complexity for HfO 2 ‐based ferroelectric (FE) devices in the complementary metal‐oxide semiconductor processes. Sputtered Hf x Zr (1‐x) O 2 (HZO) FEs have proven their thermal compatibility in back‐end‐of‐line (BEOL) integration processes with high remanent polarization (P r ) and a high cycling endurance. With the help of a tungsten oxide (WO x ) bottom electrode, the sputtered HZO's FE properties are further advanced in this work. WO x is used to tune the oxygen content in the HZO film, providing an FE performance with a maximum 2P r of 46 µC cm − 2 and an endurance of 10 8 cycles. Based on this, sputtered HZO can compete with the atomic layer deposited HZO in the BEOL processes. In addition, WO x bottom electrodes enhance the FE capacitor behavior in a broad processing window, which relaxes the manufacturing restrictions.