Modulation of Oxygen Content and Ferroelectricity in Sputtered Hafnia‐Zirconia by Engineering of Tungsten Oxide Bottom Electrodes

Abstract

Abstract The well‐developed high‐k technologies ease the integration complexity for HfO2‐based ferroelectric (FE) devices in the complementary metal‐oxide semiconductor processes. Sputtered HfxZr(1‐x)O2 (HZO) FEs have proven their thermal compatibility in back‐end‐of‐line (BEOL) integration processes with high remanent polarization (Pr) and a high cycling endurance. With the help of a tungsten oxide (WOx) bottom electrode, the sputtered HZO's FE properties are further advanced in this work. WOx is used to tune the oxygen content in the HZO film, providing an FE performance with a maximum 2Pr of 46 µC cm−2 and an endurance of 108 cycles. Based on this, sputtered HZO can compete with the atomic layer deposited HZO in the BEOL processes. In addition, WOx bottom electrodes enhance the FE capacitor behavior in a broad processing window, which relaxes the manufacturing restrictions.

Keywords

• back end of line
• ferroelectrics
• hafnium zirconium oxide
• oxygen vacancy
• sputtering
• tungsten oxide