Electrical characteristics and structural properties of ohmic contacts to p-type 4H-SiC epitaxial layers

Epitaxial films grown by low-temperature liquid phase epitaxy on p-type 4H- SiC were used as strongly doped subcontact layers for making low-resistance contacts to the p-type material. The layers had a bulk resistivity of simi lar to 0.02 Omega . cm and an aluminum atom concentration of similar to 1.5 x10(20) cm(-3). The absence of polytype inclusions and the distinct crystal line quality of the strongly doped subcontact layers was confirmed by x-ray diffraction methods. Ohmic contacts with resistivities less than 10(-4) Om ega . cm(2) were prepared by depositing and then annealing multilayer metal mixtures containing Al and Ti. The structural properties and energy charac teristics of the resulting ohmic contacts are discussed. (C) 1999 American Institute of Physics. [S1063-7826(99)01211-9].