Electrical Characteristics of SiO2 Deposited by Atomic Layer Deposition on 4H–SiC After Nitrous Oxide Anneal

Properties of SiO<sub>2</sub> gate dielectric deposited by atomic layer deposition (ALD) on Si-face of 4H silicon carbide (SiC) were systematically studied. The interface state and effective fixed charge densities of ALD SiO<sub>2</sub> on n-type 4H–SiC with various post deposition anneal (PDA) conditions were evaluated. It has been found that nitrous oxide (N<sub>2</sub>O) PDA not only reduces the effective fixed charge density, which includes the fixed oxide charge and charged interface states, at SiC/SiO<sub>2</sub> interface but also decreases the gate leakage current. Negative effective fixed charge is observed at SiC/ALD SiO<sub>2</sub> interface after N<sub>2</sub>O PDA. ALD SiO<sub>2</sub>-based lateral n-channel MOSFETs show high threshold voltage with the promising field-effect mobility and the peak field-effect mobility increases with N<sub>2</sub>O PDA temperature.

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