Applied Physics, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands.
Phys Chem Chem Phys. 2012 Dec 28;14(48):16753-9. doi: 10.1039/c2cp42275a. Epub 2012 Nov 12.
Electron-induced chemistry on surfaces plays a key role in focused electron beam induced processing (FEBIP), a single-step lithography technique that has increasingly gained interest in the past decade. It is crucial for the understanding and modelling of this process to know the role of the surface in the electron-induced dissociation of an adsorbed precursor molecule. However, the electron scattering in the underlying solid makes it impossible to determine this directly. In this paper the contribution of electron scattering in the target on the measured deposition yield is calculated for the precursor MeCpPt(IV)Me(3), using the matrix inversion method. The calculation is based on experimental data for the dissociation yield and secondary electron emission. Two trends are observed in the analysis. Firstly, the contribution of electron scattering to the experimentally determined dissociation yield is not dominant for primary electron (PE) energies up to about 50 eV. Therefore, the role of the surface in this energy range can therefore reasonably be deduced from differences between electron-induced dissociation in the gas phase and the adsorbed phase. Secondly, at PE energies above 80 eV the electron scattering contributes significantly to the measured dissociation yield. The cross section that is calculated with the matrix inversion method peaks at 80-150 eV, which is typical for gas phase ionization. This suggests that surface interactions (other than electron scattering) do not dominate the chemistry for energies above PE energies of 80 eV. The obtained result can be used as input for Monte Carlo simulations for focused electron beam induced deposition.
表面的电子诱导化学反应在聚焦电子束诱导处理（FEBIP）中起着关键作用，这是一种单步光刻技术，在过去十年中越来越受到关注。为了理解和模拟这个过程，了解表面在吸附前体分子的电子诱导离解中所起的作用至关重要。然而，由于底层固体中的电子散射，无法直接确定这一点。在本文中，使用矩阵反演法计算了吸附前体 MeCpPt(IV)Me(3)的电子诱导离解的测量沉积产率中靶材中电子散射的贡献。该计算基于离解产率和二次电子发射的实验数据。在分析中观察到两个趋势。首先，对于高达约 50 eV 的初级电子（PE）能量，电子散射对实验确定的离解产率的贡献并不占主导地位。因此，在这个能量范围内，表面的作用可以合理地从气相和吸附相中的电子诱导离解的差异中推断出来。其次，在 PE 能量高于 80 eV 时，电子散射对测量的离解产率有显著贡献。用矩阵反演法计算的截面在 80-150 eV 处达到峰值，这是气相电离的典型特征。这表明，对于高于 80 eV 的 PE 能量，表面相互作用（除了电子散射之外）不会主导化学过程。得到的结果可用于聚焦电子束诱导沉积的蒙特卡罗模拟。
