Effects of annealing temperature on the electrical property and microstructure of aluminum contact on n-type 3C-SiC

The 3C-SiC thin films used herein are grown on Si substrates by chemical vapor deposition. Al contacts with different thickness values are deposited on the 3C-SiC/Si (100) structure by the magnetron sputtering method and are annealed at different temperatures. We focus on the effects of the annealing temperature on the ohmic contact properties and microstructure of Al/3C-SiC structure. The electrical properties of Al contacts to n-type 3C-SiC are characterized by the transmission line method. The crystal structures and chemical phases of Al contacts are examined by X-ray diffraction, Raman spectra, and transmission electron microscopy, respectively. It is found that the Al contacts exhibit ohmic contact behaviors when the annealing temperature is below 550 ℃, and they become Schottky contacts when the annealing temperature is above 650 ℃. A minimum specific contact resistance of 1.8 ×10^-4 Ω·cm² is obtained when the Al contact is annealed at 250 ℃.