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 degrees C, and they become Schottky contacts when the annealing temperature is above 650 degrees C. A minimum specific contact resistance of 1.8 x 10(-4) Omega.cm(2) is obtained when the Al contact is annealed at 250 degrees C.