Transport mechanisms in focused ion beam assisted ohmic contacts to p-type 6H-SiC

摘要

The current transport mechanism in non-annealed Ohimic contact metallizations on p-type 6H-SiC formed by using focused ion beam (FIB) surface-modification and direct-write metal deposition is reported,and the properties of such focused ion beam assisted non-annealed contacts are discussed.The process uses a Ga focused ion beam to modify the surface of the semiconductor with different doses,and then introduces an organometallic compound in the Ga ion beam,to effect the direct-write deposition of a metal on the modified surface.Contact resistance measurements by the transmission line method produced values in the low 10~(-4) cm~2 range for surface-modified and direct-write Pt and W non-annealed contacts,and mid 10~(-5) cm~2 range for surface-modified and pulse laser deposited TiN contacts.The current transport mechanism of these contacts was examined and found to proceed mainly by tunneling through the metal-modified-semiconductor interface layer.