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用卢瑟福背散射(RBS)和同步辐射X射线衍射(XRD)研究了p-GaN上的Ni/Au电极在空气下不同温度合金后的微结构的演化,并揭示这种接触结构的欧姆接触形成机制.研究不同温度下比接触电阻(ρc)的变化,发现从450℃开始Au扩散到GaN的表面在p-GaN上形成外延结构以及O向电极内部扩散反应生成NiO对降低ρc起到了关键的作用.在500℃时,Au的外延结构进一步改善,O进一步向样品内部扩散生成NiO,ρc也达到了最低值.但当合金温度升高到600℃时,金属半导体界面NiO的大部分或全部向外扩散,从而脱离与pGaN的接触,使ρc显著升高.
The evolution of the microstructures of Ni / Au electrodes on p-GaN at different temperatures under air was investigated by Rutherford backscattering (RBS) and synchrotron radiation X-ray diffraction (XRD), and the ohmic Contact formation mechanism.Studying the change of specific contact resistance (ρc) at different temperatures, we found that Au diffused to the surface of GaN from 450 ℃ to form an epitaxial structure on the p-GaN and O diffusion into the electrode to generate NiO to reduce ρc At 500 ℃, the epitaxial structure of Au is further improved, O further diffuses into the sample to form NiO, and ρc also reaches the lowest value.When the temperature of the alloy increases to 600 ℃, most of the NiO interface Or all outwardly diffuse out of contact with pGaN, causing ρc to increase significantly.