单晶硅低能电子束辐照效应

利用Monter-Carlo方法,模拟低能一维平面电子束在本征、不同掺杂类型、掺杂浓度下的单晶Si中能量沉积分布情况。采用电子顺磁共振(EPR)技术测量了(111)晶向、两种掺杂类型下的掺杂浓度分别为1×1015cm-3、1×1017cm-3的单晶硅片在一定电子注量下辐照前后缺陷顺磁吸收谱,比较了样品辐照前后缺陷顺磁中心强度的变化,并用X光电子能谱(XPS)对Si-SiO2系统原子化学态的变化进行分析。结果表明,相比于P型Si,N型Si、特别是高掺杂的N型Si,在低能电子一定注量下,界面区内易引起辐射感生缺陷,主要来自于键合于磷的非桥联氧对空穴的诱捕作用,表现为POHC中心明显的变化,P2P芯能级谱突变。并根据理论和实验结果,对电子能量沉积、电离缺陷和辐照效应间的相互关系进行了分析。

Radiation Effects on Single-crystal Silicon of Low Energy Electron Beam

The energy deposition for electron beam with low energy on Si specimens was calculated by Monter-Carlo method.Making use of electron paramagnetic resonance（EPR） technique,the investigation of the effects of EPR signal variations in dopant type and concentration was carried out by using P-type and N-type（111） silicon wafers with concentrations of 1×10¹5cm^-3 and 1×10¹7cm^-3,respectively,before and after the irradiation of electrons,and the intensities of defect paramagnetic centers before and after irradiation of electron were compared.The chemical states of Si-SiO₂ system were determined by X-ray photoelectron spectroscopy（XPS）.The results clearly indicate that the effects of dopant variations（type and concentration） are of obvious difference.Compared with P type silicon,specially,N type silicon with a high dopant concentration tends to produce defects at interface under low energy electron irradiation with certain flux,which arise from the hole trapped on a non-bridging oxygen atom bonded to P.It is embodied in the form of distinct changes of POHC intensity and P₂P binding energy.According to the theory and experimental data,the relationship among electron energy deposition,ionizing damage and radiation effect was analyzed and discussed.