Ferroelectric Hafnium Nitride Thin Films Directly Formed on Si(100) Substrate

• Published in: IEEE Journal of the Electron Devices Society
• Main Authors: S. Ohmi, Y. Ohtaguchi, A. Ihara, H. Morita
• Format: Article
• Language: English
• Published: IEEE 2021-01-01
• Subjects: Hafnium nitride; ferroelectrics; rhombohedral phase; MFS diode; ECR plasma; reactive sputtering
• Online Access: https://ieeexplore.ieee.org/document/9590540/
• ISSN: 2168-6734

We have investigated the ferroelectric hafnium nitride (HfN) thin films directly formed on the Si(100) substrate for the metal-ferroelectrics-Si field-effect transistor (MFSFET) applications. The 10 nm thick rhombohedral phase HfN layer was found to be formed on the Si(100) substrate utilizing the post-metallization annealing (PMA) at 400&#x00B0;C/5 min for HfN_0.5/HfN_1.15/Si(100) MFS diode structure which was deposited with in situ process by the electron cyclotron resonance (ECR) plasma reactive sputtering. The remnant polarization (2P_r) of <inline-formula> <tex-math notation="LaTeX">$24.0 \mu \text{C}$ </tex-math></inline-formula>/cm² with the coercive field (<inline-formula> <tex-math notation="LaTeX">${\text{E}_{c}}$ </tex-math></inline-formula>) of 3.8 MV/cm was obtained from the P-V characteristic under the voltage sweep of &#x00B1;10 V. Fatigue characteristics without wake-up were confirmed until 10⁹ program/erase (P/E) cycles under the input pulses of &#x00B1;6 V/<inline-formula> <tex-math notation="LaTeX">$5 \mu \text{s}$ </tex-math></inline-formula> although the 2<inline-formula> <tex-math notation="LaTeX">${\text {P}_{r}}$ </tex-math></inline-formula> was gradually decreased to <inline-formula> <tex-math notation="LaTeX">$10.7 \mu \text{C}$ </tex-math></inline-formula>/cm². The polarization (P_sw) of <inline-formula> <tex-math notation="LaTeX">$13.4 \mu \text{C}$ </tex-math></inline-formula>/cm² was clearly observed by the positive-up negative-down (PUND) measurements utilizing the input pulses of &#x00B1;6 V/<inline-formula> <tex-math notation="LaTeX">$5 \mu \text{s}$ </tex-math></inline-formula>. The memory window (MW) of 0.32 V was realized in the C-V characteristics by the program operation at &#x2212;10 V/1 s.