Growth and the Microstructural and Ferroelectric Characterization of Oriented BAMGF4 Thin Films

For the first time the growth of ferroelectric BaMgF4 thin films on Si(100), sapphire (1102), and other substrates under ultrahigh vacuum (UHV) conditions is reported. Microstructural characterization of the films using transmission electron microscopy (TEM) revealed that they were oriented crystalline films, although not epitaxial. Ferroelectric hysteresis measurements yielded spontaneous polarization and coercivity values of almost 1.0 μC/cm2 and 160 kV/cm respectively. The discrepancy with the bulk ferroelectric values were attributed to the electrical contacts, impurities in the film, and lack of polar axis orientation. Preliminary capacitance-voltage (C-V) hysteresis measurements on a 480 nm thick BaMgF4 film yielded a 10.8-V threshold shift (memory window) in response to a – 10-V programming voltage for a MIS gate structure similar to that of the ferroelectric memory field effect transistor (FEMFET).