Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands.
Nanotechnology. 2010 Nov 12;21(45):455302. doi: 10.1088/0957-4484/21/45/455302. Epub 2010 Oct 14.
A 25 keV focused helium ion beam has been used to grow PtC nanopillars on a silicon substrate by beam-induced decomposition of a (CH(3))(3)Pt(C(P)CH(3)) precursor gas. The ion beam diameter was about 1 nm. The observed relatively high growth rates suggest that electronic excitation is the dominant mechanism in helium ion-beam-induced deposition. Pillars grown at low beam currents are narrow and have sharp tips. For a constant dose, the pillar height decreases with increasing current, pointing to depletion of precursor molecules at the beam impact site. Furthermore, the diameter increases rapidly and the total pillar volume decreases slowly with increasing current. Monte Carlo simulations have been performed with realistic values for the fundamental deposition processes. The simulation results are in good agreement with experimental observations. In particular, they reproduce the current dependences of the vertical and lateral growth rates and of the volumetric deposition efficiency. Furthermore, the simulations reveal that the vertical pillar growth is due to type-1 secondary electrons and primary ions, while the lateral outgrowth is due to type-2 secondary electrons and scattered ions.
采用 25keV 聚焦氦离子束，通过（CH(3))(3)Pt(C(P)CH(3))前体气体的束诱导分解，在硅衬底上生长 PtC 纳米柱。离子束直径约为 1nm。观察到的相对较高的生长速率表明，电子激发是氦离子束诱导沉积的主要机制。在低束流下生长的柱子很窄，并且有尖锐的尖端。对于恒定的剂量，随着电流的增加，柱高降低，这表明在束流撞击点前体分子耗尽。此外，随着电流的增加，直径迅速增加，总柱体积缓慢减少。使用基本沉积过程的实际值进行了蒙特卡罗模拟。模拟结果与实验观察结果非常吻合。特别是，它们再现了垂直和横向生长速率以及体积沉积效率的电流依赖性。此外，模拟表明，垂直柱生长是由于类型-1 二次电子和初级离子，而侧向生长是由于类型-2 二次电子和散射离子。
