Growth of Epitaxial Cu/TiN/6H-SiC(0001) Heterostructures by Pulsed Laser Deposition

Epitaxial Cu/TiN heterostructures were grown on hexagonal (6H)-SiC(0001) substrate by pulsed laser deposition using the domain epitaxy, where integral multiple of lattice constant or major planes match across the interface1. Such layers are needed for metallization of SiC bond integrated circuit devices. These Cu and TiN layers on SiC(0001) were grown at 600 degrees centigrade in a high vacuum (<10−6 Torr). This structure was characterized using X-ray diffraction technique and transmission electron microscopy. The X-ray diffraction recorded only (111) and (222) reflection of Cu and TiN. The full-width at half maximum of ω-rocking curve of (111) reflection of Cu (0.4 degree) and TEM results indicated a high epitaxial quality. The plan view transmission electron micrograph shows that Cu forms three-dimensional islands indicating that the Cu/TiN interface energy is very high. The island size varies from 0.2 to 2 μm. Analysis of selective aperture diffraction patterns and cross-sectional transmission electron microscopy, including high-resolution imaging, showed relationships Cu(111)//TiN(111)//6H-SiC(0001). The TiN/SiC an interface was locally atomically sharp and free from secondary phases or obvious interdiffusion. The typical defects in the TiN(111) layers consisted of threading domain boundaries. The mechanism of three-dimension growth of copper on TiN layers was discussed.