低能质子在半导体材料Si和GaAs中的非电离能损研究

Non-ionizing energy loss of low energy proton in semiconductor materials Si and GaAs

非电离能损(NIEL)引起的位移损伤是导致空间辐射环境中新型光电器件失效的主要因素.由于低能时库仑相互作用占主导地位,一般采用Mott-Rutherford微分散射截面,但它没考虑核外电子库仑屏蔽的影响.为此,本文采用解析法和基于Monte-Carlo方法的SRIM程序计算了考虑库仑屏蔽效应后低能质子在半导体材料Si,GaAs中的NIEL,SRIM程序在计算过程中采用薄靶近似法,并与其他作者的计算数据和实验数据进行了比较.结果表明:用SRIM程序计算NIEL时采用薄靶近似法处理是比较合理的,同时考虑库仑屏蔽效应后的NIEL较没考虑前要小,当能量为1keV时,Si材料中NIEL的值为Summers结果的30%,GaAs材料中为20%,这在航天设计中有着重要的意义.

The displacement damage due to non-ionizing energy loss （NIEL） is the main reason of device-malfunction in spatial radiation environments. In the low energy range where the Coulombic interaction dominates, Mott-Rutherford differential cross section is usually used in its creatment. However, electrostatic screening of nuclear charges of interacting particles is not accounted for. The NIEL induced by low energy proton in Si and GaAs have been calculated using analytical method and Monte- Carlo code （SRIM）. Thin-target approximation was used when calculating NIEL by SRIM code and the result compared with that of other authors＇ . The results show that thin-target approximation is reasonable and NIEL scaling is feasible. The NIEL values become lower after taking into account the screening effect. The results by SRIM code are 30% and 20% of Summers＇ s results for Si and GaAs at 1 keV, respectively. The result is very important for spacecraft design.