《Journal of Electronic Materials》
Correlation between the Electrical Properties and the Interfacial Microstructures of TiAl-Based Ohmic Contacts to p-Type 4H-SiC
作者:
S Trapido
关键词:
TiAl-based;p-type 4H-SiC;ohmic contact;microstructure;Ti3SiC2
摘要:
In order to understand a mechanism of TiAl-based ohmic contact formation for p-type 4H-SiC, the electrical properties and microstructures of Ti/Al and Ni/Ti/Al contacts, which provided the specific contact resistances of approximately 2 × 10Ω-cmand 7 × 10Ω-cmafter annealing at 1000°C and 800°C, respectively, were investigated using x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Ternary TiSiCcarbide layers were observed to grow on the SiC surfaces in both the Ti/Al and the Ni/Ti/Al contacts when the contacts yielded low resistance. The TiSiCcarbide layers with hexagonal structures had an epitaxial orientation relationship with the 4H-SiC substrates. The (0001)-oriented terraces were observed periodically at the interfaces between the carbide layers and the SiC, and the terraces were atomically flat. We believed the TiSiCcarbide layers primarily reduced the high Schottky barrier height at the contact metal/p-SiC interface down to about 0.3 eV, and, thus, low contact resistances were obtained for p-type TiAl-based ohmic contacts.
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