Liu Bangzhi, Wang Yanfeng, Dilts Sarah, Mayer Theresa S, Mohney Suzanne E
Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Nano Lett. 2007 Mar;7(3):818-24. doi: 10.1021/nl062393r. Epub 2007 Feb 13.
The solid-state reaction between platinum and silicon nanowires grown by the vapor-liquid-solid technique was studied. The reaction product PtSi is an attractive candidate for contacts to p-type silicon nanowires due to the low barrier height of PtSi contacts to p-type Si in the planar geometry, and the formation of PtSi was the motivation for our study. Silicidation was carried out by annealing Pt on Si nanowires from 250 to 700 degrees C, and the reaction products were characterized by transmission electron microscopy. Strikingly different morphologies of the reacted nanowires were observed depending on the annealing temperature, platinum film thickness, silicon nanowire diameter, and level of unintentional oxygen contamination in the annealing furnace. Conversion to PtSi was successfully realized by annealing above 400 degrees C in purified N2 gas. A uniform morphology was achieved for nanowires with an appropriate combination of Si nanowire diameter and Pt film thickness to form PtSi without excess Pt or Si. Similar to the planar silicidation process, oxygen affects the nanowire silicidation process greatly.
研究了通过气-液-固技术生长的铂与硅纳米线之间的固态反应。反应产物PtSi是用于与p型硅纳米线形成接触的有吸引力的候选材料，这是因为在平面几何结构中，PtSi与p型硅之间的接触势垒较低，而PtSi的形成是我们开展这项研究的动机。通过在250至700摄氏度的温度范围内对硅纳米线上的铂进行退火来实现硅化，并用透射电子显微镜对反应产物进行表征。根据退火温度、铂膜厚度、硅纳米线直径以及退火炉中无意引入的氧污染程度的不同，观察到反应后的纳米线呈现出显著不同的形态。在纯化的氮气中于400摄氏度以上退火可成功实现向PtSi的转变。对于具有适当的硅纳米线直径和铂膜厚度组合以形成PtSi且没有过量的铂或硅的纳米线，可实现均匀的形态。与平面硅化过程类似，氧对纳米线硅化过程有很大影响。
