Epitaxial integration of ferroelectric and conductive perovskites on silicon
Abstract
BaTiO3 (BTO) and LaxSr1 − xTiO3 (x ≤ 0.15) perovskite heterostructures are deposited epitaxially on SrTiO3 (STO)-buffered Si(001) via atomic layer deposition (ALD) to explore the formation of a quantum metal layer between a ferroelectric film and silicon. X-ray diffraction and scanning transmission electron microscopy show the crystallinity of the heterostructure deposited by ALD. After postdeposition annealing of the La-doped STO film in ultrahigh vacuum at 600 °C for 5 min, x-ray photoelectron spectra show the lack of La-dopant activation when the film is deposited on 10 nm-thick BTO. The same postdeposition annealing condition activates the La-dopant when LaxSr1 − xTiO3 films are deposited on STO-buffered Si(001) surfaces consisting of 2.8 nm of STO(001) on Si(001). Annealing of LaxSr1 − xTiO3 films sandwiched between BTO and STO-buffered Si(001) layers in air at temperatures ≤350 °C preserves the La-dopant activation. Piezoresponse force microscopy demonstrates the ferroelectric behavior of BTO films grown on LaxSr1 − xTiO3 surfaces. Sheet resistance and capacitance-voltage measurements further demonstrate the conductivity of the LaxSr1 − xTiO3 films sandwiched between the BTO film and the Si(001) substrate.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 13, 2020
- Source ID
- 10.1116/1.5134077
Entities
People
- Agham Posadas
- Alexander A Demkov
- Brennan M. Coffey
- Davis J. Smith
- Edward L. Lin
- Hsin Wei Wu
- John G Ekerdt
- Keji Lai
- Lu Zheng
- Pei-yu Chen
Organizations
- Air Force Office of Scientific Research
- Arizona State University
- National Science Foundation
- University of Texas at Austin