Study of the Bonding Characteristics at β-Ga2O3(201)/4H-SiC(0001) Interfaces from First Principles and Experiment

Abstract

For the first time, β-Ga2O3 were prepared on 4H-SiC (0001) substrates using a low-pressure chemical vapor deposition (LPCVD) technique. The obtained β-Ga2O3/4H-SiC heterostructures display strongly preferential growth orientation along the <201> of β-Ga2O3. Combining the experimental results, interfacial properties, such as the work of adhesion (Wad), electronic properties and bonding characteristics of β-Ga2O3(201)/4H-SiC(0001) heterointerface were systemically studied using first principles. Four different β-Ga2O3(201)/4H-SiC(0001) interface models composed of different atom stacking sequences were established. It was found that the interface consisting of silicon terminated of 4H-SiC (0001), and oxygen terminated of β-Ga2O3(201) (Si-O) has the lowest relaxation energy and the highest stability. Results indicated that the binding of interface Si and C to the O atoms is stronger than that to the Ga atoms. The results of the difference charge density and electron localization function reveals that the Si and C atoms at interface are bonded with O atoms of β-Ga2O3 by covalent bonds, in which Si-O and C-O covalent bonds play a favorable role in the final stable configurations formation. This work will provide a further understanding of the various electronic behaviors of the β-Ga2O3(201)/4H-SiC(0001) heterointerface.

Band Alignment of β-Ga2O3 with BaTiO3, SrTiO3, and Related Composites

“…Characterizations and analyze of Ga 2 O 3 films.-The XRD characterization of sample 1# is shown in Fig. 1a, the diffraction peak near 41.70°corresponded to α-Al 2 O 3 (0006), and the peaks at 18.91°, 38.37°, and 59.02°originated from the β-phase of Ga 2 O 3 (−201), (−402), and (−603) (JCPDS 43-1012), 23,24 respectively. It reflects that the phase of LPCVD-grown β-Ga 2 O 3 films are preferentially selective orientation along the (−201) plane, and own decent crystal quality.…”

“…High purity gallium metal (⩾99.9999%) was used as gallium source, then, Oxygen (O 2 , 5 N) and Argon (Ar, 5 N) were used as oxygen precursor and carrier gas, respectively. 23,24 Further deposition details of β-Ga 2 O 3 could be found in previous work. 23 Following, a 30 nm thick perovskite oxides (BaTiO 3 , SrTiO 3 , Ba 0.5 Sr 0.5 TiO 3 (named as BSTO)) were then deposited on β-Ga 2 O 3 by RF PVD (Kurt J Lesker-PVD75) in O 2 ambience with a flow rate of 20 sccm.…”