Improvements in the electrical performance of high voltage 4H-SiC Schottky diodes by hydrogen annealing

• A significant improvement in all the important parameters of the diodes were observed by annealing in H-2 at 300 degreesC. The forward current increased from 55 mA to 100 mA at a bias voltage of 2.5 V. The reverse leakage current measured at -500 V was reduced from 3.5 x 10(-9) to 4.8 x 10(-10) Amps for a 0.5 mm diameter diode. The average value of the barrier height increased by at least 0.2 eV, measured by Capacitance-Voltage and Current-Voltage technique indicating the increase of both static and effective barrier heights. The average value of ideality factor also improved and a best value of 1.06 was obtained for the hot-wall CVD grown samples after Hz annealing. Hydrogen atoms may passivate the dangling bends at the metal-semiconductor interface and thus by saturating the dangling bonds reduce the interface state density.

Nyckelord

dangling bond

hydrogen annealing

interface state density

power devices

Schottky diodes

TECHNOLOGY

TEKNIKVETENSKAP

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