Strong Fermi-level pinning induced by argon inductively coupled plasma treatment and post-metal deposition annealing on 4H-SiC

The effect of pre–metal deposition cleaning on 4H-SiC Schottky barrier diodes (SBDs) by using Ar ion bombardment in an inductively coupled plasma (ICP) chamber was investigated. The ICP treatment produced a thin and Si-depleted amorphous layer on the SiC surface. Partial graphitization was observed in the amorphous layer after post-metal deposition (PMD) annealing. This interfacial layer strongly pinned the Schottky barrier height (SBH). PMD annealing at 500 °C resulted in a constant SBH (approximately 1.1 eV) and narrow SBH distribution (standard deviation < 3 meV). However, the amorphous layer was consumed after 600 °C PMD annealing due to interfacial reactions. These results suggest that the Ar ion bombardment technique with a suitable thermal budget can be used to form relatively uniform SBDs.