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研究了n型碳化硅(SiC)极性表面、载流子浓度和退火温度对欧姆接触的影响,测试了不同样品的电流-电压曲线,并通过传输线方法计算比接触电阻。对于SiC衬底的硅面,GeNiTiAu合金材料的欧姆接触特性最好;而对于碳面,TiAu合金材料的接触电阻最小。衬底载流子浓度由1.5×101 7cm-3逐步提高到2.0×1018cm-3,金属与n型SiC衬底硅面的接触由肖特基接触变为欧姆接触,欧姆接触电阻随着载流子浓度的提高而明显降低。GeTiAu合金与SiC衬底硅面的接触电阻随着退火温度的提高非单调降低,900℃为最优退火温度。原子力显微镜结果显示,退火后样品表面粗糙度明显提高。
The influence of the n-type silicon carbide (SiC) polar surface, carrier concentration and annealing temperature on the ohmic contact was investigated. The current-voltage curves of different samples were tested and the specific contact resistance was calculated by transmission line method. The ohmic contact properties of GeNiTiAu alloy materials are best for the silicon surface of SiC substrate, and the contact resistance of TiAu alloy materials is the smallest for the carbon surface. Substrate carrier concentration gradually increased from 1.5 × 101 7cm-3 to 2.0 × 1018cm-3, the contact of the metal with the silicon surface of the n-type SiC substrate changed from Schottky contact to ohmic contact, and the ohmic contact resistance increased with the carrier current Sub-concentration increased significantly reduced. The contact resistance between the GeTiAu alloy and the silicon surface of SiC substrate decreases non-monotonously with the increase of annealing temperature, and 900 ℃ is the optimal annealing temperature. AFM results show that the surface roughness of the sample is significantly increased after annealing.