Effect of SiC crystal orientation on Ti3SiC2 formation between SiC and Al/Ti bi-layered film

The present study was performed to understand the interfacial reaction between Al/Ti bi-layered films and 4H-SiC with various surface orientations and the preferential growth orientation of Ti3SiC2 crystals. To this end, n-type 4H-SiC crystals oriented to the (0001), (1 (1) over bar 00), and (11 (2) over bar0) surfaces were prepared. The (0001) and (11 (2) over bar0) surfaces of the p-type 4H-SiC were composed of commercially available p-type 4H-SiC wafers; these surfaces were tilted by 8 degrees from (0001) towards [11 (2) over bar0] by the dicing and polishing of the wafers. Using the same method, another surface orientation was achieved wherein the surface was tilted by 30 degrees from (11 (2) over bar0) towards [0001]. Further, Al/Ti bi-layered films were deposited on each SiC substrate, using the radio-frequency magnetron sputtering method, which was followed by the stepwise annealing. The microstructures were examined by X-ray diffractometry and transmission electron microscopy. The Ti3SiC2 phase grew epitaxially in the [11 (2) over bar0](SiC) orientation on the (0001) surface of 4H-SiC. Ti3SiC2 phase did not grow uniformly on the other SiC surfaces that were oriented to (1 (1) over bar 00) or (11 (2) over bar0). The Ti3SiC2 phase growth was columnar and parallel to (0001)(SiC) in the [11 (2) over bar0](SiC) orientation on the SiC surface tilted by 30. from (11 (2) over bar0) towards [0001]. The electrical characteristics of p-type 4H-SiC contact films measured before and after annealing revealed that the characteristics of Al/Ti/ (11 (2) over bar0)(4H-SiC) were improved after annealing.