Demonstration of High Ferroelectricity (P$_{{r}}$ ~ 29 $\mu$ C/cm2) in Zr Rich HfxZr1–xO2 Films

Dipjyoti Das,Sanghun Jeon,Venkateswarlu Gaddam

doi:10.1109/led.2019.2955198

Abstract

In this letter, we report excellent ferroelectricity with high remanent polarization (Pr) in Zr rich hafnium zirconium oxide (HZO) films using high pressure post metallization annealing (HPPMA). HZO films annealed using rapid thermal annealing (RTA) show highest ferroelectricity when the Hf:Zr ratio is 1:1 and exhibit antiferroelectric property for Zr rich films. However, under HPPMA, Zr rich films demonstrate enhanced ferroelectric property as compared to 1:1 HZO films and the best result was observed for 1:3 HZO films. The HZO (1:3) films by HPPMA show P r as high as ~ 29 μC/cm 2 , which is almost 50% higher than that achieved for the best condition of RTA (P r ~ 19 μC/cm 2 ). Besides, due to the presence of high Zr, the HZO (1:3) films by HPPMA exhibit considerably higher dielectric constant (k ~ 43) and low coercive field (E c ~ 1.21 MV/cm) as compared to that of HZO (1:1) films by RTA (k ~ 37, E c ~ 1.35 MV/cm). We believe the enhanced ferroelectricity in Zr rich HZO films can be due to more o/t-phase formation in ZrO 2 under HPPMA as compared to that of RTA. On the other hand, more m-phase formation was observed in HfO 2 under HPPMA, resulting in a significant drop of P r in case of Hf rich HZO. The demonstration of enhanced ferroelectric properties by Zr rich HZO films can be helpful for high functional semiconductor device applications.

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