Yoon Young Joon, Chae S W, Kim B K, Park Min Joo, Kwak Joon Seop
Fusion Technology Team, Korea Institute of Ceramic Engineering and Technology, Seoul 153-801, Korea.
J Nanosci Nanotechnol. 2010 May;10(5):3254-9. doi: 10.1166/jnn.2010.2280.
Interfacial microstructure and elemental diffusion of Cu-doped indium oxide (CIO)/indium tin oxide (ITO) ohmic contacts to p-type GaN for light-emitting diodes (LEDs) were investigated using cross-sectional transmission electron microscopy (XTEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction. The CIO/ITO contacts gave specific contact resistances of approximately 10(-4) omegacm2 and transmittance greater than 95% at a wavelength of 405 nm when annealed at 630 degrees C for 1 min in air. After annealing at 630 degrees C, multi-component oxides composed of Ga2O3-In2O3, Ga2O3-CuO, and In2O3-CuO formed at the interface between p-GaN and ITO. Formation of multi-component oxides reduced the barrier height between p-GaN and ITO due to their higher work functions than that of ITO, and caused Ga in the GaN to diffuse into the CIO/ITO layer, followed by generation of acceptor-like Ga vacancies near the GaN surface, which lowered contact resistivity of the CIO/ITO contacts to p-GaN after the annealing.
采用截面透射电子显微镜（XTEM）、X射线光电子能谱（XPS）和X射线衍射对用于发光二极管（LED）的铜掺杂氧化铟（CIO）/氧化铟锡（ITO）与p型GaN的欧姆接触的界面微观结构和元素扩散进行了研究。当在空气中630℃退火1分钟时，CIO/ITO接触的比接触电阻约为10（-4）Ω·cm2，在405nm波长处的透过率大于95%。在630℃退火后，在p-GaN和ITO之间的界面处形成了由Ga2O3-In2O3、Ga2O3-CuO和In2O3-CuO组成的多组分氧化物。多组分氧化物的形成降低了p-GaN和ITO之间的势垒高度，因为它们的功函数高于ITO，并导致GaN中的Ga扩散到CIO/ITO层中，随后在GaN表面附近产生类似受主的Ga空位，这降低了退火后CIO/ITO与p-GaN接触的接触电阻率。
