Demonstration of BEOL-compatible ferroelectric Hf_0.5Zr_0.5O₂ scaled FeRAM co-integrated with 130nm CMOS for embedded NVM applications

Abstract

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Dual-Storage-Port Nonvolatile SRAM Based on Back-End-of-the-Line Processed Hf0.5Zr0.5O₂ Ferroelectric Capacitors Towards 3D Selector-Free Cross-Point Memory

“…30s was employed to form the ferroelectric phase. The compatibility of the HZO-based ferroelectric capacitors using the same annealing temperature as the CMOS process was also demonstrated recently by T. Francois et al [10], which suggests their potential for mass production. During the electrical measurements of these stand-alone MFM capacitors, the top electrodes were biased with the bottom electrodes grounded.…”

“…The demonstrated endurance of the HZO ferroelectric capacitors ensure the NVSRAM devices are capable of sufficient power-down/RECALL cycles. The HZO ferroelectric capacitors can reliably retain their polarization states at room temperature and elevated temperatures [10], contributing to the robust data retention of the NVSRAM cells [6]. Successful RECALL has been experimentally demonstrated over 14 hours after power-down.…”

“…Miwa et al proposed and demonstrated a 6-transistor-2-capacitor (6T2C) NVSRAM, based on conventional perovskite ferroelectrics, which are difficult to scale beyond the 130 nm node [2]. Recently, ferroelectricity has been demonstrated in the HfxZr1-xO2 (HZO) material system fabricated at relatively low annealing temperatures (≤ 450 0 C), suggesting the possibility of fabrication using the Back-End-of-the-Line (BEOL) process [7][8][9][10][11]. M. Kobayashi et al successfully demonstrated functionalities of the NVSRAM with the same 6T2C configuration using the newly discovered HZO- 1 Manuscript received XX; revised XX; accepted XX.…”

Ferroelectric Hf0.5Zr0.5O2 Thin Films Crystallized by Pulsed Laser Annealing

“…[1,2] Unlike perovskite materials, doped HfO 2 films are perfectly compatible with the existing complementary metal-oxide-semiconductor technology (e.g., as reported in various studies [3][4][5][6] ) One of the most promising representatives of this class of materials is an alloyed HfO 2 ÀZrO 2 thin film, particularly, at the Hf 0.5 Zr 0.5 O 2 (HZO) stoichiometry, for which the annealing temperature required for the crystallization of the ferroelectric phase is as low as T ¼ 400 C, [7][8][9][10][11] thus potentially enabling to fabricate ferroelectric devices in the back-end-of-line process. [5,6] The experimental studies conducted to date [9][10][11][12][13][14][15] point at the metastable noncentrosymmetric orthorhombic phase (Pbc2 1 or Pca2 1 ) [16] to be responsible for the ferroelectric properties of doped or alloyed HfO 2 films. To stabilize this phase and suppress the formation of an equilibrium monoclinic phase (P2 1 /c), rapid thermal annealing (RTA) process is used.…”

Ferroelectric, Analog Resistive Switching in Back‐End‐of‐Line Compatible TiN/HfZrO4/TiOx Junctions

“…Their fabrication is challenging as the ferroelectric layer must be thick enough to stabilize ferroelectricity, a fortiori in multiple configurations, but thin enough to allow electric conduction. These conditions have been obtained for polycrystalline HZO at temperatures above 450 C. [21][22][23][24][25] A reduced thermal budget is less critical for thicker films: 10 nm layers have been, for example, crystallized at 400 C. [26][27][28] In this article, we demonstrate nonvolatile resistive switching (memristive functionality) in a 4.5 nm-thick ferroelectric layer in a BEOL compatible stack. A reduced thermal budget (%375 C) is used as well as abundant and CMOS compatible materials (Hf, Zr, and Ti).…”