【Member Papers】Spectroscopic Calculation of Band Alignment Between High Permittivity Composites ZrSiO, AlSiO and β-Ga₂O₃

Basic information

      A research team by Prof. Chen Chengying and Teacher Zhang Hongpeng from Xiamen University of Technology published a paper titled “Spectroscopic Calculation of Band Alignment Between High Permittivity Composites ZrSiO, AlSiO and β-Ga₂O₃” in Journal: ECS Journal of Solid State Science and Technology.

Funding

      This research was supported by the National Natural Science Foundation of China (NSFC) (Grant No. U21A20501, 62474139, 62404186) and the Science and Technology Plan Project of Xiamen City (No. 3502Z20227070). The project was funded by 3502Z20206074 and the Major Science and Technology Project of Xiamen City (No. 3502Z20221022).

Background

      β-phase gallium oxide (β-Ga₂O₃) has become a promote candidate for the next generation of power devices and deep ultraviolet detectors due to its superior properties such as ultra-wide bandgap (4.9 eV) and high critical breakdown field strength (8 MV/cm), as well as the increasingly mature single crystal preparation and epitaxial growth technologies. Among them, the MOS structure is widely used in β-Ga₂O₃ power devices (such as transistors, MOS-Type diodes or device passivation layers) and photodetectors to improve the gate control performance and reliability of the devices. In order to fulfill the advantage of high breakdown field strength of β-Ga₂O₃, integrating MOS structures with β-Ga₂O₃ and high dielectric constant dielectric (high k dielectric) is regarded as one of the solutions for effectively regulating the gate and surface electric fields. For example, HfO₂, HfSiO, HfAlO, and even higher k choice such as BaTiO₃ and SrTiO₃ have been successively reported to be used in β-Ga₂O₃ transistor and diodes to adjust the gate control and electric field, effectively enhance the device breakdown field strength, and have great application potential. Therefore, based on our previous studies (such as HfAlO/β-Ga₂O₃,BaTiO₃/β-Ga₂O₃,SrTiO₃/β-Ga₂O₃, etc.), our team explored the band structure of β-Ga₂O₃ in the high-K composite ZrSiO, AlSiO. Provide experimental inspiration and guidance for the development of high-performance β-Ga₂O₃ based electronic devices.

Main Content

      This paper systematically studies the microstructure, film quality, band structure and interfacial characteristics of high-K composites ZrSiO and AlSiO films grown on β-Ga₂O₃ films. In this study, β-Ga₂O₃ films and ZrSiO, AlSiO films were prepared respectively by low-pressure chemical vapor deposition (LPCVD) technology and radio frequency magnetron sputtering (RF PVD) technology. Advanced characterization techniques, including X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and X-ray diffraction (XRD), were used to clarify the surface morphology, crystal structure, atomic bonding, and band order of the prepared films. These results show that the β-Ga₂O₃ and ZrSiO, AlSiO films prepared based on the above process and appropriate growth parameters have good film quality and surface flatness (low RMS). Furthermore, through the analysis of characterization data, it can be known that both the heterojunctions ZrSiO/β-Ga₂O₃ and AlSiO/β-Ga₂O₃ form a nested I-type band structures. It also has extremely large conduction band offsets (1.74 ± 0.03 and 2.30 ± 0.02 eV respectively) and valence band offsets (0.41 ± 0.03 and 0.76 ± 0.02 eV respectively), which can effectively hinder carrier transportation and reduce the leakage current of the MOS structure.

      This study explored the film quality, interface characteristics and band order of ZrSiO/β-Ga₂O₃ and AlSiO/β-Ga₂O₃ heterojunctions, providing experimental inspiration and theoretical guidance for the development of high-performance wide bandgap semiconductor devices.

Innovation

      The heterojunctions ZrSiO/β-Ga₂O₃ and AlSiO/β-Ga₂O₃ were systematically studied for the first time by using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and X-ray diffraction (XRD).

      Study the ZrSiO AlSiO, β-Ga₂O₃ crystal structure, surface morphology, illuminates the ZrSiO/β-Ga₂O₃ and AlSiO/β-Ga₂O₃ band structure and can take order.

      The studies provides experimental inspiration and theoretical guidance for developing high performance β-Ga₂O₃ devices, combined with proposing two potential high k solution for β-Ga₂O₃ power devices.