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Effects of Low Temperature Electronic Cyclotron Resonance Hydrogen Plasma Treatment and Annealing on the Electrical Properties of Ti and Ni Contacts to 4H-SiC

2012; Institute of Physics; Volume: 51; Issue: 8R Linguagem: Inglês

10.1143/jjap.51.081302

1347-4065

Lingqin Huang, Qiaozhi Zhu, Mingchao Gao, Fuwen Qin, Dejun Wang,

Copper Interconnects and Reliability

The effects of low temperature electronic cyclotron resonance microwave hydrogen plasma pretreatment and post-annealing on the electrical properties of Ti and Ni contacts to 4H-SiC were investigated. The HPT improves the Ohmic behavior of Ti/4H-SiC contact significantly. In contrast, it remarkably enhances the rectifying behavior of Ni/4H-SiC contact. The properties of Ti Ohmic contact and Ni rectifying contact improve with increasing annealing temperature up to 400 °C. However, they are deteriorated above 400 °C. X-ray photoelectron spectroscopy measurements confirm that the surface Fermi level ( E F s ) moves toward the conduction band edge by the HPT. It almost attains the bulk Femi level position after annealing at 400 °C with the surface states density ( D s ) as low as 4.43×10 11 cm -2 eV -1 . However, after annealing above 400 °C, E F s moves back closer to midgap with an increase of D s . The experimental results are found to obey the barrier height theory of Cowley and Sze.