Epitaxial growth of barium hexaferrite film on wide bandgap semiconductor 6H–SiC by molecular beam epitaxy

Abstract

Epitaxial barium ferrite (BaM) films have been successfully grown by molecular beam epitaxy (MBE) for the first time on 6H silicon carbide substrates by using a 10 nm single crystalline MgO (1 1 1)//SiC(0 0 0 1) template, also grown by MBE. X-ray photoelectron spectroscopy showed that the thin MgO template in the early stages of film growth prevented the diffusion of Si into the BaM film. Background oxygen pressure (containing both O atoms and O2, but no ionic species) is critical for determining the chemistry and surface structure of BaM. An oxygen deficient or rich environment will cause impurity phases of Fe3O4 or α-BaFe2O4, respectively. For BaM films grown in an optimal oxygen environment, x-ray diffraction showed a strong c-axis perpendicular to the substrate plane while the pole figure exhibited reflections consistent with epitaxial growth. Vibrating sample magnetometry showed a perpendicular magnetic anisotropy field of 16 200 Oe and a magnetization (as 4πM s) of 4.1 kG.

M-Type Barium Hexagonal Ferrite Films

“…In 2010, Cai et al demonstrated the MBE growth of both MgO buffer layers and BaM thin films on 6H-SiC substrates. 14 The MgO layers were grown at a substrate temperature of 150 C. For the growth of BaM films, the substrate temperature was set to 800 C.…”

“…Emphasis has been placed on the optimization of deposition processes for low-loss, self-biased BaM thin films, 7,8,9,10 the deposition of BaM thin films on "non-conventional" substrates, such as semiconductor substrates 11,12,13,14 and metallic substrates, 15 the fabrication of BaM thick films on semiconductor substrates, 16,17 the demonstration of BaM-based planar mm-wave devices, 18,19,20,21,22,23,10,24 the development of BaM-based ferromagnetic/ferroelectric heterostructures, 25,26,27,28,29 and the study of multiferroic effects in single-phase BaM materials. 30 A variety of different techniques have been used to fabricate BaM film materials.…”

“…30 A variety of different techniques have been used to fabricate BaM film materials. These include pulsed laser deposition (PLD), 7,8,9,10,11,12,28,31 liquid phase epitaxy (LPE), 32,33,34,35 RF magnetron sputtering, 36,37,19,38,39,40 molecular beam epitaxy (MBE), 14 metallo-organic decomposition (MOD), 15 chemical vapor deposition (CVD), 41 and screen printing. 16,17 The device demonstration includes both numerical 20,21,22 and experimental efforts.…”

“…15 Section 3.3 reviews the deposition of BaM thin films on semiconductor substrates by PLD and MBE techniques. 13,14 Section 3.4 describes the fabrication of BaM thick films on semiconductor substrates by screen printing. 16,17 Section 4 reviews the demonstration of BaM thin film-based mm-wave notch filters 10,24 and phase shifters.…”

M-type barium hexaferrite synthesis and characterization for phase shifter applications

“…7 While these properties are important in determining hexaferrites' utility as microwave materials, they also have excellent radiation resistance and high power handling capacities that make them ideal for next-generation microwave devices, especially for use in extreme environments. 8,9 The structure of the hexaferrites is unique in that all the observed structures, including M type, Y type, Z type and so on, are made up of common subunits that are present in different numbers and repeat sequences. 4,10 All subunits are built upon a close packed lattice of oxygen with different metal ion arrangements.…”