Two-inch semi-insulating SiC bulk crystals with resistivity higher than 1 × 10^6 Qcm were achieved by vanadium doping during sublimation. Secondary-ion-mass-spectrometry （SIMS） was employed to determine the con...Two-inch semi-insulating SiC bulk crystals with resistivity higher than 1 × 10^6 Qcm were achieved by vanadium doping during sublimation. Secondary-ion-mass-spectrometry （SIMS） was employed to determine the concentration of impurities in the crystals, such as B, AI, V and N. These results indicated that the concentration of nitrogen and aluminum kept on decreasing and the concentration of B and V was almost constant during the whole growth. An inner crucible was used to control the exhausting of vanadium, which made the uniformity of the high resistivity （〉1×10^6 Ωcm） in the wafer up to 80%. High-performance AlGaN/GaN high-electronmobility-transistor （HEMT） materials and devices were grown and fabricated on semi-insulating 6H-SiC sub- strates. The two-dimensional electron gas （2DEG） mobility at room-temperature was 1795 cm^2/V-s. The charge carrier concentration of the substrate determined by capacitance-voltage （C-V） test was 7.3×10^15 cm^-3. The device with a gate width of I mm exhibits a maximum output power of 5.5 W at 8 GHz, which proves the semi-insulating property of the substrates indirectly.展开更多
基金supported by the National Natural Sci-ence Foundation of China under grant No. 50472068 and No. 50721002the National "863" High Technology Re-search and Development Program of China under grant No. 2006AA03A145 and No. 2007AA03Z405+1 种基金the Na-tional Basic Research Program of China under grant No.2009CB930503the Cultivation Fund of the Key Scientific and Technical Innovation Project, Ministry of Education of China under grant No. 707039
文摘Two-inch semi-insulating SiC bulk crystals with resistivity higher than 1 × 10^6 Qcm were achieved by vanadium doping during sublimation. Secondary-ion-mass-spectrometry （SIMS） was employed to determine the concentration of impurities in the crystals, such as B, AI, V and N. These results indicated that the concentration of nitrogen and aluminum kept on decreasing and the concentration of B and V was almost constant during the whole growth. An inner crucible was used to control the exhausting of vanadium, which made the uniformity of the high resistivity （〉1×10^6 Ωcm） in the wafer up to 80%. High-performance AlGaN/GaN high-electronmobility-transistor （HEMT） materials and devices were grown and fabricated on semi-insulating 6H-SiC sub- strates. The two-dimensional electron gas （2DEG） mobility at room-temperature was 1795 cm^2/V-s. The charge carrier concentration of the substrate determined by capacitance-voltage （C-V） test was 7.3×10^15 cm^-3. The device with a gate width of I mm exhibits a maximum output power of 5.5 W at 8 GHz, which proves the semi-insulating property of the substrates indirectly.
