Abstract

The effect of the microrelief, dislocation structure, and other defects of epitaxial layers in the source and drain regions of a Nitride High Electron Mobility Transistor (НЕМТ) on the parameters of the formed ohmic contacts is discussed. The investigations are carried out directly on the chips of power microwave transistors manufactured on the GaN/AlGaN/GaN/SiC heterostructures. The ohmic fired contacts are formed with the use of Ti–Al–Mo–Au and Ti–Al–Ni–Au compositions. The microrelief of the surface on the interface of the fired contact/AlGaN and the defects formed on it is investigated in order to estimate the structural features of the contact areas. It is found that the resistance of the source and drain regions are determined to a considerable extent by the microstructure of the surface on the boundary. The formation of the conductive layer in AlGaN under an ohmic fired contact is shown by the experiments. The possibility of the formation of a new type of structural defect with a high aspect ratio in the contact and active areas of the devices at the formation of ohmic fired contacts is demonstrated. It is shown that the existence of high densities of such defects results in an increase of the leakage currents of the devices.

中文翻译：

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工艺因素对功率AlGaN / GaN / SiC-HEMT欧姆接触特性的影响

摘要

讨论了氮化物高电子迁移率晶体管（НЕМТ）的源极和漏极区中的微浮雕，位错结构和外延层的其他缺陷对所形成的欧姆接触的参数的影响。研究直接在GaN / AlGaN / GaN / SiC异质结构上制造的功率微波晶体管的芯片上进行。使用Ti–Al–Mo–Au和Ti–Al–Ni–Au成分形成欧姆点火触点。为了评估接触区域的结构特征，研究了烧结后的触点/ AlGaN界面上的表面的微浮雕及其上形成的缺陷。发现源极和漏极区域的电阻在很大程度上由边界上的表面的微观结构决定。实验显示了在AlGaN欧姆接触下导电层的形成。证明了在形成欧姆烧制接触时在器件的接触和有源区域中形成高纵横比的新型结构缺陷的可能性。结果表明，这种缺陷的高密度存在导致器件漏电流的增加。