ガリウム・ヒ素化合物半導体用の超新機能電極材料の研究

本实验室研制出了在未来GaAs器件中有应用前景的NiInGe欧姆接触材料。虽然NiInGe接触提供了约0.3 Ω-mm的低接触电阻和优异的热稳定性，但是为了将这些接触应用于亚微米器件中，必须进一步减小NiInGe接触的接触电阻（Rc）。在这项研究项目中，影响Rc值的微观结构参数进行了研究，通过相关的Rc值与接触材料和GaAs之间的界面处的微观结构。发现NiInGe接触的Rc值强烈地依赖于在金属/GaAs界面处形成的In_xGa_ As化合物半导体层的体积分数和In浓度（x）<1-x>。In_xGa_ As层的体积分数和In浓度均<1-x>取决于NiInGe接触中所用In层的厚度和形成欧姆接触的退火温度。Ni（18 nm）/In（13 nm）/Ge（30 nm）接触在650 ℃退火5s后，电阻率达到0.18 Ω·mm。

NiInGe Ohmic contact materials which are attractive to use in the future GaAs devices were developed in our laboratories. Although the NiInGe contacts provided low contact resistances of around 0.3 Ω-mm and excellent thermal stability, further reduction of the contact resistance (Rc) of the NiInGe contacts was mandatory to apply these contacts in the sub-micron devices. In this research project, the microstructural parameters which influence the Rc values were investigated by correlating the Rc values with the microstructure at the interface between the contact materials and GaAs. The Rc values of the NiInGe contacts were found to depend strongly on the volume fraction and the In concentration (x) of the In_xGa_<1-x>As compound semiconductor layers which were formed at the metal/GaAs interface. Both the volume fraction and the In concentration of the In_xGa_<1-x>As layers were found to depend on the thickness of the In layer used in the NiInGe contact and the annealing temperature to form the Ohmic contacts. The Rc value of 0.18 Ω-mm was obtained for the Ni(18nm)/In(13nm)/Ge(30nm) contact after annealing at temperature of around 650 ℃ for 5 s where a slash "/" indicates the deposition sequence.