Fig. 2: Dielectric properties of KBBF thin layers.
From: High-κ KBe2BO3F2 dielectric material with wide bandgap for two-dimensional electronics
a The structure diagram and b a false-coloured scanning electron microscope (SEM) image of the metal–insulator–metal (MIM) device. Scale bar, 5 μm. c Voltage-dependent capacitance density for MIM devices of 12 nm-thick KBBF layer at five different frequencies. Inset, frequency-dependent capacitance density at four different voltages. d Dielectric constant and equivalent oxide layer thickness (EOT) as a function of various KBBF thickness measured from MIM capacitors. The gray line is the fitted curve according to the dead layer model. e Bandgap of KBBF obtained from density functional theory (DFT) calculation. f Bandgap versus dielectric constant of typical dielectrics5,9,10,12,13,15,19,29,30,31,32,33,34,35,36,37,57,58,59,60. The dashed black line serves as a guide to illustrate the inverse proportionality between these two properties. g Time-dependent dielectric breakdown (TDDB) versus stress voltage characteristics of KBBF, where the black dash-line represents the lifetime prediction. Inset: Time-dependent breakdown curves of KBBF at various voltage stresses.
