Impact of Al-Interlayer Processing on the Properties of 4H-SiC Schottky Diodes

Abstract

We report on the improvement in device performance of SiC Schottky barrier diodes (SBDs) by forming aluminium carbide (Al4C3) at metal-SiC interface. Al interlayer was annealed at 700 and 1000 degrees C and the bonding of Al-C was detected by measurement of XPS. The current density and leakage current of device with Al4C3 interlayer was similar to 1.6 A/cm(2) at 5 V and leakage current of less than similar to 1.2x10(-9) at -5 V, respectively. The experimental results demonstrate that the device with Al4C3 has higher Schottky barrier height and yields on-off ratio of 2.4x10(8), which is 12 times higher than that of device without Al4C3. The results suggest that the bonding of Al-C may be responsible for the decrease of leakage current by increase of Schottky barrier height.