EFFECT OF REACTIVE ION ETCH-INDUCED DAMAGE ON THE PERFORMANCE OF 4H-SIC SCHOTTKY-BARRIER DIODES

The effect of reactive ion etch (RIE) induced damage on 4H-SiC surface s etched in fluorinated plasmas has been investigated and characterize d using Ni Schottky diodes and x-ray photoelectron spectroscopic surfa ce analysis. The diodes were characterized using current-voltage, curr ent-voltage-temperature, and capacitance-voltage measurements with nea r ideal forward characteristics (n = 1.07) and forward current density as high as 9000 A/cm(2) from the control (unetched) devices. High cur rent handling capability was observed in diodes with etched surfaces a s well. Diodes with surfaces etched in CHF3 containing plasmas showed a significant reduction in the barrier height compared to the diodes w ith surfaces etched in CF4 containing plasma. Control devices exhibite d high leakages when reverse biased, which is attributed to the presen ce of a thin (similar to 2 nm) oxide layer at the metal-semiconductor interface. However, under reverse bias diodes with CHF3-etched surface s showed improvement in leakage current compared to diodes with CF4-et ched surfaces and the control diodes.