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Atomic layer deposited(ALD) Al2O3 /dry-oxidized ultrathin SiO2 films as a high-k gate dielectric grown on 8°off-axis 4H-SiC(0001) epitaxial wafers are investigated in this paper.The metal-insulation-semiconductor(MIS) capacitors,respectively with different gate dielectric stacks(Al2O3/SiO2,Al2O3,and SiO2) are fabricated and compared with each other.The I-V measurements show that the Al2O3/SiO2 stack has a high breakdown field(≥12 MV/cm) comparable to SiO2,and a relatively low gate leakage current of1×10-7A/cm2 at an electric field of4 MV/cm comparable to Al2O3.The 1-MHz high frequency C-V measurements exhibit that the Al2O3/SiO2 stack has a smaller positive flat-band voltage shift and hysteresis voltage,indicating a less effective charge and slow-trap density near the interface.
Atomic layer deposited (ALD) Al2O3 / dry-oxidized ultrathin SiO2 films as a high-k gate dielectric grown on 8 ° off-axis 4H-SiC (0001) epitaxial wafers are investigated in this paper. ) capacitors, respectively with different gate dielectric stacks (Al2O3 / SiO2, Al2O3, and SiO2) are fabricated and compared with each other. The IV measurements show that the Al2O3 / SiO2 stack has a high breakdown field (> 12 MV / cm) to SiO2, and a relatively low gate leakage current of 1 × 10-7 A / cm2 at an electric field of 4 MV / cm comparable to Al2O3. 1-MHz high frequency CV measurements exhibit that the Al2O3 / SiO2 stack has a smaller positive flat- band voltage shift and hysteresis voltage, indicating a less effective charge and slow-trap density near the interface.