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A 4H-silicon carbide metal-insulator-semiconductor structure with ultra-thin Al 2 O 3 as the gate dielectric,deposited by atomic layer deposition on the epitaxial layer of a 4H-SiC (0001) 8 0 N-/N+ substrate,has been fabricated.The experimental results indicate that the prepared ultra-thin Al 2 O 3 gate dielectric exhibits good physical and electrical characteristics,including a high breakdown electrical field of 25 MV/cm,excellent interface properties (1×10 14 cm-2) and low gate-leakage current (I G=1 × 10-3 A/cm-2 @E ox=8 MV/cm).Analysis of the current conduction mecha-nism on the deposited Al 2 O 3 gate dielectric was also systematically performed.The confirmed conduction mechanisms consisted of Fowler-Nordheim (FN) tunneling,the Frenkel-Poole mechanism,direct tunneling and Schottky emission,and the dominant current conduction mechanism depends on the applied electrical field.When the gate leakage current mechanism is dominated by FN tunneling,the barrier height of SiC/Al 2 O 3 is 1.4 eV,which can meet the requirements of silicon carbide metal-insulator-semiconductor transistor devices.
A 4H-silicon carbide metal-insulator-semiconductor structure with ultra-thin Al 2 O 3 as the gate dielectric, deposited by atomic layer deposition on the epitaxial layer of a 4H-SiC (0001) 8 0 N- / N + substrate, has has been fabricated. The experimental results indicate that the prepared ultra-thin Al 2 O 3 gate dielectric exhibits good physical and electrical characteristics, including a high breakdown electrical field of 25 MV / cm, excellent interface properties (1 × 10 14 cm -2) and low gate-leakage current (IG = 1 × 10 -3 A / cm -2 @E ox = 8 MV / cm) .Analysis of the current conduction mecha-nism on the deposited Al 2 O 3 gate dielectric was also systematically performed . The confirmatory influential consisted of Fowler-Nordheim (FN) tunneling, the Frenkel-Poole mechanism, direct tunneling and Schottky emission, and the dominant current conduction mechanism depends on the applied electrical field.When the gate leakage current mechanism is dominated by FN tunneling, the barrier height of SiC / Al 2 O 3 is 1.4 eV, which can meet the requirements of silicon carbide metal-insulator-semiconductor transistor devices.