PTCDA/P-Si光电探测器欧姆接触层的XPS测试分析

XPS Test Analysis of Ohmic Contact Layer of Photodetector

在光电探测器PTCDA/P-Si芯片的有机层表面,成功制作出了比接触电阻为4.5×10-5Ω·cm2的低阻欧姆接触层。利用X射线光电子能谱(XPS)对Al/Ni/ITO的欧姆接触层界面的电子状态进行了测试和分析。结果表明,ITO中的In3d及Sn3d各出现两个分裂能级的谱峰,它们是In和Sn原子处于氧化环境的结合能。Ni2p有两个谱峰Ni2p(1)及Ni2p(2),低结合能位置Ni2p(1)对应于Ni原子被X射线激发产生的谱峰,说明NiITO之间没有发生化学反应,Ni层阻止了Al层被氧化成Al2O3;高结合能Ni2p(2)谱峰说明已形成了Al3Ni冶金相,有利于低阻欧姆接触层的形成。

Low Ohmic contact layers with the specific contact resistance of 4. 5 × 10-5Ω·cm2were fabricated on the organic layer surface of PTCDA / P-Si photodetector chip. The electronic states of the interface of Al / Ni / ITO structure Ohmic contact layer were investigated using X-ray photoelectron spectroscopy( XPS). In ITO,In3 dand Sn3darise two peaks of split level,respectively. They are the binding energy of In and Sn atom located in oxidizing environment. Ni2 phas two spectra peaks of Ni2p( 1)and Ni2p( 2). The lower binding energy location is Ni2p(1)which is excited by X-ray. It indicates that no chemical reaction happens between Ni and ITO layer,and the formation of A12O3 has been prevented. As for Ni2p( 2)peak,it indicates that Al3 Ni alloy phase has formed,which is good for the formation of low resistance Ohmic contact layer.