Boost of orthorhombic population with amorphous SiO2 interfacial layer—a DFT study. (1st May 2022)

• Record Type: Journal Article
• Authors: Chen, Yun-Wen; Liu, C W
• Is Part Of: Semiconductor science and technology. Volume 37:Number 5(2022)
• Publication Date: 2022-05-01
• Subjects: ferroelectric (FE) -- anti-ferroelectric (AFE) -- interfacial energy; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1361-6641/ac5a5e
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: Via the density functional theory, the phase diagrams of HZO thin film in MFM (M = TiN, F = HZO) and MFI (I = α -SiO2 ) structures are constructed with dependences on grain size and temperature. In both MFM and MFI, the region for orthorhombic phase (o-phase) in phase diagram grows when HZO thickness gets thinner. Comparing to MFM, HZO/ α -SiO2 interface in MFI suppresses the growth of tetragonal phase (t-phase) to the region of very small grain size ∼1.2 nm. The simulation results agree with the experimental observation by Cheema et al, that the enhanced FE property was obtained in a MFIS (S = silicon) device with ultrathin HZO film (<2 nm). Simulation model indicates more chemical bonds forming between HZO and α -SiO2 interface could stabilize o-phase to greatly enhance the FE property in a MFIS device.