Ferroelectric HfO_2 formation by annealing of a HfO_2/Hf/HfO_2/Si(100) stacked structure

摘要

In this research, ferroelectric characteristics of HfO2 formed by annealing of a HfO2/Hf/HfO2/Si(100) stacked structure were investigated. It was found that the HfO2/Hf/HfO2 stacked structure enhanced the formation of a metastable orthorhombic phase HfO2 on Si(100) substrate by a post-deposition annealing (PDA) process at a low-temperature of 600 degrees C. The remnant polarization (2P(r)) of 20 mu C cm(-2) was obtained, which is larger than the 14 mu C cm(-2) observed in the diode without a 1 nm thick Hf interlayer. However, the C-V characteristics with ferroelectric hysteresis was not obtained because its coercive field (2E(c)) was as high as 9.6 MV cm(-1). On the other hand, the diode with a post-metallization annealing process induced the memory window of 0.9 Vat the sweep range from -4 to 4 V in spite of smaller P-r in its P-V characteristic than that of the diode with PDA process. (C) 2019 The Japan Society of Applied Physics