High thickness uniformity and large-scale films of α-Ga_(2)O_(3) are crucial factors for the development of power devices.In this work, a high-quality 2-inch α-Ga_(2)O_(3) epitaxial film on c-plane sapphire substrat...High thickness uniformity and large-scale films of α-Ga_(2)O_(3) are crucial factors for the development of power devices.In this work, a high-quality 2-inch α-Ga_(2)O_(3) epitaxial film on c-plane sapphire substrates was prepared by the mist-CVD method.The growth rate and phase control mechanisms were systematically investigated. The growth rate of the α-Ga_(2)O_(3) films was limited by the evaporation of the microdroplets containing gallium acetylacetonate. By adjusting the substrate position(z) from 80 to 50 mm, the growth rate was increased from 307 nm/h to 1.45 μm/h when the growth temperature was fixed at 520 °C.When the growth temperature exceeded 560 °C, ε-Ga_(2)O_(3) was observed to form at the edges of 2-inch sapphire substrate.Phase control was achieved by adjusting the growth temperature. When the growth temperature was 540 °C and the substrate position was 50 mm, the full-width at half maximum(FWHM) of the rocking curves for the(0006) and(10-14) planes were 0.023° and 1.17°. The screw and edge dislocations were 2.3 × 10~6 and 3.9 × 10~(10)cm~(-2), respectively. Furthermore, the bandgaps and optical transmittance of α-Ga_(2)O_(3) films grown under different conditions were characterized utilizing UV-visible and near-IR scanning spectra.展开更多
As a wide-bandgap semiconductor(WBG), β-Ga_2O_3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga_2O_3 single crystals were summarized, including dislo...As a wide-bandgap semiconductor(WBG), β-Ga_2O_3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga_2O_3 single crystals were summarized, including dislocations, voids, twin, and small defects. Their effects on device performance were discussed. Dislocations and their surrounding regions can act as paths for the leakage current of SBD in single crystals. However, not all voids lead to leakage current. There's no strong evidence yet to show small defects affect the electrical properties. Doping impurity was definitely irrelated to the leakage current. Finally, the formation mechanism of the defects was analyzed. Most small defects were induced by mechanical damages. The screw dislocation originated from a subgrain boundary. The edge dislocation lying on a plane slightly tilted towards the(102) plane, the(101) being the possible slip plane. The voids defects like hollow nanopipes, PNPs, NSGs and line-shaped grooves may be caused by the condensation of excess oxygen vacancies, penetration of tiny bubbles or local meltback. The nucleation of twin lamellae occurred at the initial stage of "shoulder part" during the crystal growth. These results are helpful in controlling the occurrence of crystal defects and improving the device performance.展开更多
Owing to the advantages of ultra-wide bandgap and rich material systems,gallium oxide(Ga_(2)O_(3))has emerged as a highly viable semiconductor material for new researches.This article mainly focuses on the growth proc...Owing to the advantages of ultra-wide bandgap and rich material systems,gallium oxide(Ga_(2)O_(3))has emerged as a highly viable semiconductor material for new researches.This article mainly focuses on the growth processes,material characteristics,and applications of Ga_(2)O_(3).Compared with single crystals and the epitaxial growth of other wide-bandgap semiconductors,large-size and high-quality𝛽-Ga_(2)O_(3) single crystals can be efficiently grown with a low cost,making them highly competitive.Thanks to the availability of high-quality single crystals,epi-taxial films,and rich material systems,high-performance semiconductor devices based on Ga_(2)O_(3) go through a booming development in recent years.The defects and interfaces of Ga_(2)O_(3) are comprehensively analyzed owing to their significant influence on practical applications.In this study,the two most common applications of Ga_(2)O_(3) materials are introduced.The high breakdown electric field,high working temperature,and excellent Baliga’s figure-of-merit of Ga_(2)O_(3) represent an inspiring prospect for power electronic devices.In addition,the excellent absorption in deep-ultraviolet band provides new ideas for optoelectronic detectors and ensures the dramatic progress.Finally,the summary,challenges,and prospects of the Ga_(2)O_(3) materials and devices are presented and discussed.展开更多
基金National Natural Science Foundation of China (Grant Nos. 52002219, 51932004 and 61975098)Key-Area Research and Development Program of Guangdong Province (Grant No. 2020B010174002)+2 种基金Shenzhen Fundamental Research Program (Grant No. JCYJ20210324132014038)Natural Science Foundation of Shandong (Grant No. ZR202105230005)the 111 Project 2.0 (Grant No. BP2018013)。
文摘High thickness uniformity and large-scale films of α-Ga_(2)O_(3) are crucial factors for the development of power devices.In this work, a high-quality 2-inch α-Ga_(2)O_(3) epitaxial film on c-plane sapphire substrates was prepared by the mist-CVD method.The growth rate and phase control mechanisms were systematically investigated. The growth rate of the α-Ga_(2)O_(3) films was limited by the evaporation of the microdroplets containing gallium acetylacetonate. By adjusting the substrate position(z) from 80 to 50 mm, the growth rate was increased from 307 nm/h to 1.45 μm/h when the growth temperature was fixed at 520 °C.When the growth temperature exceeded 560 °C, ε-Ga_(2)O_(3) was observed to form at the edges of 2-inch sapphire substrate.Phase control was achieved by adjusting the growth temperature. When the growth temperature was 540 °C and the substrate position was 50 mm, the full-width at half maximum(FWHM) of the rocking curves for the(0006) and(10-14) planes were 0.023° and 1.17°. The screw and edge dislocations were 2.3 × 10~6 and 3.9 × 10~(10)cm~(-2), respectively. Furthermore, the bandgaps and optical transmittance of α-Ga_(2)O_(3) films grown under different conditions were characterized utilizing UV-visible and near-IR scanning spectra.
基金the Financial support from the National key Research and Development Program of China(Nso.2018YFB0406502,2016YFB1102201)the National Natural Science Foundation of China(Grant No.51321091)+2 种基金the key Research and Development Program of Shandong Province(No.2018CXGC0410)the Young Scholars Program of Shandong University(No.2015WLJH36)the 111 Project 2.0(No.BP2018013)
文摘As a wide-bandgap semiconductor(WBG), β-Ga_2O_3 is expected to be applied to power electronics and solar blind UV photodetectors. In this review, defects in β-Ga_2O_3 single crystals were summarized, including dislocations, voids, twin, and small defects. Their effects on device performance were discussed. Dislocations and their surrounding regions can act as paths for the leakage current of SBD in single crystals. However, not all voids lead to leakage current. There's no strong evidence yet to show small defects affect the electrical properties. Doping impurity was definitely irrelated to the leakage current. Finally, the formation mechanism of the defects was analyzed. Most small defects were induced by mechanical damages. The screw dislocation originated from a subgrain boundary. The edge dislocation lying on a plane slightly tilted towards the(102) plane, the(101) being the possible slip plane. The voids defects like hollow nanopipes, PNPs, NSGs and line-shaped grooves may be caused by the condensation of excess oxygen vacancies, penetration of tiny bubbles or local meltback. The nucleation of twin lamellae occurred at the initial stage of "shoulder part" during the crystal growth. These results are helpful in controlling the occurrence of crystal defects and improving the device performance.
基金supported by the National Natural Science Foun-dation of China(Grants No.61925110,U20A20207,61821091,62004184,62004186,61774081,62004147,51932004,52002219,and 51961145110)the Ministry of Science and Technology of China(Grant No.2018YFB0406500)+6 种基金the Strategic Priority Research Pro-gram of the Chinese Academy of Sciences(Grant No.XDB44000000)the Key Research Program of Frontier Sciences of the CAS(Grant No.QYZDB-SSW-JSC048)the Key-Area Research and Development Program of Guangdong Province(Grant No.2020B010174002)the Fundamental Research Funds for the Central Universities under(Grants No.WK2100000014 and WK2100000010)funding sup-port from the University of Science and Technology of China(Grant No.KY2100000109)the China Postdoctoral Science Foundation(Grants No.2020M671895 and BX20200320)the Opening Project of the Key Laboratory of Microelectronics Devices and Integration Technology at the Institute of Microelectronics of CAS,and the Key Laboratory of Nanodevices and Applications in Suzhou Institute of Nano-Tech and Nano-Bionics of CAS。
文摘Owing to the advantages of ultra-wide bandgap and rich material systems,gallium oxide(Ga_(2)O_(3))has emerged as a highly viable semiconductor material for new researches.This article mainly focuses on the growth processes,material characteristics,and applications of Ga_(2)O_(3).Compared with single crystals and the epitaxial growth of other wide-bandgap semiconductors,large-size and high-quality𝛽-Ga_(2)O_(3) single crystals can be efficiently grown with a low cost,making them highly competitive.Thanks to the availability of high-quality single crystals,epi-taxial films,and rich material systems,high-performance semiconductor devices based on Ga_(2)O_(3) go through a booming development in recent years.The defects and interfaces of Ga_(2)O_(3) are comprehensively analyzed owing to their significant influence on practical applications.In this study,the two most common applications of Ga_(2)O_(3) materials are introduced.The high breakdown electric field,high working temperature,and excellent Baliga’s figure-of-merit of Ga_(2)O_(3) represent an inspiring prospect for power electronic devices.In addition,the excellent absorption in deep-ultraviolet band provides new ideas for optoelectronic detectors and ensures the dramatic progress.Finally,the summary,challenges,and prospects of the Ga_(2)O_(3) materials and devices are presented and discussed.