Lamination method for improved polarization-leakage current relation in HfO2-based metal/ferroelectric/insulator/semiconductor structure. (1st April 2022)

• Record Type: Journal Article
• Authors: Kim, Yeonwoo; Min, Kyung Kyu; Yu, Junsu; Kwon, Daewoong; Park, Byung-Gook
• Is Part Of: Semiconductor science and technology. Volume 37:Number 4(2022)
• Publication Date: 2022-04-01
• Subjects: hafnium oxide (HfO2) -- ferroelectricity -- laminated metal/ferroelectric/insulator/semiconductor structure -- ferroelectric tunnel junction; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1361-6641/ac4edd
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: Ever since the ferroelectricity of complementary metal-oxide semiconductor (CMOS) compatible HfO2 -based materials was discovered, numerous studies have been conducted on their ferroelectric (FE) properties and device applications. In particular, pure-HfO2 FE materials without external doping have attracted considerable attention owing to their excellent robustness against variation because variations that appear in conventional doped-HfO2 FEs are not observed in electrical characteristics induced by dopant fluctuations in pure-HfO2 FEs. Studies on metal/FE/insulator/semiconductor (MFIS) stack are required to apply the ferroelectricity of pure-HfO2 to memory devices that are completely compatible with Si-based CMOS processes. In pure-HfO2 based MFIS stacks, the polarization tends to reduce with increasing thickness of the HfO2, although the leakage current diminishes. To overcome the tradeoff between the polarization and leakage current with respect to the thickness of the HfO2, an Al2 O3 layer was inserted between the HfO2 layers to form a laminated FE structure. By employing the laminated FE, leakage current was effectively suppressed by the Al2 O3 and lower HfO2 layers, and polarization was enhanced by the FE sum of the upper and lower HfO2 layers. Therefore, an MFIS structure with maximized polarization and minimized leakage current was successfully demonstrated using laminated FE. In addition, the feasibility of the proposed MFIS with laminated FE for nonvolatile memory device applications was confirmed by verifying the multistate operations of a FE tunnel junction.