Correlation between the electrical properties and the interfacial microstructures of TiAl-based ohmic contacts to p-type 4H-SiC
Correlation between the electrical properties and the interfacial microstructures of TiAl-based ohmic contacts to p-type 4H-SiC
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DOI：
10.1007/s11664-004-0203-x
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发表时间：
2004-05-01
影响因子：
2.1
通讯作者：
Murakami, M
中科院分区：
文献类型：
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作者：
Tsukimoto, S;Nitta, K;Murakami, M
为了了解p型4H-SiC钛基欧姆接触形成的机理，利用X射线衍射（XRD）和高分辨率透射电镜（HRTEM）研究了Ti/Al和Ni/Ti/Al接触在1000℃和800℃退火后的电学性能和微观结构，分别获得了约2 X 10(-5) ω -cm(2)和7 X 10(-5) ω -cm(2)的特定接触电阻。当Ti/Al触点和Ni/Ti/Al触点产生低电阻时，均在SiC表面生长出Ti3SiC2三元碳化物层。具有六边形结构的Ti3SiC2碳化物层与4H-SiC衬底呈外延取向关系。在碳化物层与碳化硅的界面处周期性地观察到（0001）取向的台阶，并且这些台阶是原子平面的。我们认为，Ti3SiC2碳化物层主要将接触金属/p-SiC界面处的高肖特基势垒高度降低到约0.3 eV，从而获得了p型tial基欧姆接触的低接触电阻。
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 X 10(-5) Omega-cm(2) and 7 X 10(-5) Omegacm(2) after annealing at 1000degreesC and 800degreesC, respectively, were investigated using x-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). Ternary Ti3SiC2 carbide 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 Ti3SiC2 carbide 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 Ti3SiC2 carbide 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.