Process influences on the microstructure of BEoL integrated ferroelectric hafnium zirconium oxide

The back-end-of-line (BEoL) integration of ferroelectric hafnium zirconium oxide (HZO) has many advantages for applications like non-volatile memories and sensors. Using transmission Kikuchi diffraction (TKD), the influence of process parameters like annealing conditions and Zr content on the microstructure are investigated here. TKD analysis allows to map the local crystallographic phase and orientations as well as grain size and shape. The results of this study present thereby no significant dependence of the grain size, shape and phase on the annealing time. However, Zr content affects the microstructure strongly, and decrease in grain size and monoclinic phase as well as changes in the crystallographic texture are observed for higher Zr content. How this affects the polarization behavior is investigated as well.