Materials Science Forum, Vol.353-356, 251-254, 2001
Origin of the excellent thermal stability of Al/Si-based ohmic contacts to p-type LPE 4H-SiC
Two types of ohmic contacts, namely AlSiTi and Al/Si, have been formed on p-type 4H-SiC grown by LPE. An increase of the optimum annealing temperature was observed for the contacts containing titanium. The lowest resistivity of 9.5x10(-5) Omega .cm(2) of AlSiTi/SiC contacts was achieved after annealing at 950 degreesC and a value of 2.5x10(-4) Omega .cm(2) was measured for Al/SiSiC contacts annealed at 700 degreesC. It was found that AlSiTi contacts were stable during aging at 600 degreesC for 100 h while Al/Si contacts deteriorated after 48 h heating. This result can be ascribed to the formation of a stable Al(4)C(3) compound in the AlSiTi/SiC contacts annealed at 950 degreesC.