Invited; HfZrO-based ferroelectric capacitors and FETs for ultralow-power signal processing
Conference Dates
May 15-18, 2023
Abstract
Since the discovery of ferroelectricity in HfO2-based dielectric films in 2011 [1], MFM capacitors and FETs using HfO2-based thin films as dielectrics have attracted strong interest. Thus, active research and developments have been conducted for various applications including memory, logic, and AI computing with extremely low power consumption. In this paper, we introduce our recent research on a variety of HfZrO2 (HZO)-based ferroelectric devices such as FeRAM [2-3], FeFET memory [4-8], anti-ferroelectric FETs [9-10] and reservoir computing devices [11-13], for ultralow-power signal processing.The high polarization reversal voltage associated with the high coercive field of HZO films makes it difficult to achieve the low voltage operation of HZO FeRAM. Here, scaling HZO film thickness is effective in a reduction of the supply voltage of FeRAM with HZO MFM capacitors. It has been found through a systematic study on ferroelectric characteristics of Hf0.5Zr0.5O2 films with a thickness from 9.5 to 2.8 nm [2, 3] that scaling HZO film thickness to 4-5 nm can reduce operating voltage below 1 V (~0.8 V) with sufficient 2Pr by performing 106 cycles of wakeup. Also, the electric field causing dielectric breakdown can significantly increase by HZO scaling. The experimental endurance characteristic of 4-nm-thick HZO has indicated that the maximum cycle times determined by dielectric breakdown is around 1010 and 1012 times at 4 MV/cm and 3 MV/cm (1.2 V), respectively, under a pulse voltage operation of 200 kHz.
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Recommended Citation
Shinichi Takagi, Kasidit Toprasertpong, Eishin Nako, Xuan Luo, Mitsuru Takenaka, and Ryosho Nakane, "Invited; HfZrO-based ferroelectric capacitors and FETs for ultralow-power signal processing" in "Semiconductor Technology for Ultra Large Scale Integrated Circuits and Thin Film Transistors (ULSIC VS TFT 8)", Y. Kuo, Texas A&M University, USA Eds, ECI Symposium Series, (2022). https://dc.engconfintl.org/ulsic_vs_tft_8/41