BaTiO3/SrTiO3 heterostructures for ferroelectric fieldeffect transistors

• Published in: Applied physics letters 2017-06, Vol.110 (23)
• Main Authors: Shoron, Omor F, Raghavan Santosh, Freeze, Christopher R, Stemmer, Susanne
• Format: Article
• Language: English
• Subjects: Applied physics; Barium titanates; Electric potential; Epitaxial growth; Ferroelectric materials; Ferroelectricity; Field effect transistors; Heterostructures; Hysteresis; Molecular beam epitaxy; Parallel plates; Semiconductor devices; Strontium titanates; Thin films; Transistors; Voltage gain
• ISSN: 0003-6951; 1077-3118

Integration of ultrathin ferroelectric thin films with semiconductors is of interest fornegative capacitancetransistors thatexhibit internal voltage gain, which may allow for scaling the supply voltage of low powercircuits. In this study, BaTiO3 thin films were grown on doped SrTiO3channels using molecular beam epitaxy. The BaTiO3films areferroelectricdespite their low thickness (∼10 nm). Parallel plate capacitor devices exhibitanti-clockwise hysteresis, and a comparison with reference structures withoutBaTiO3 shows that the polarization in the BaTiO3 thinfilms isswitchable and controls the chargedensity in the channel. Field effect transistors were fabricated to study theeffect of ferroelectricity on the transistor characteristics. Anti-clockwise hysteresis and a shift inthreshold-voltage are observed in the output characteristics of the transistors. These propertiesmake these heterostructures a suitable system for studying negative capacitance effects.