Structure function relationship in electronic thin films

本论文主要研究两类薄膜的结构与功能的关系：一类是由有机半导体分子制成的薄膜，另一类是由金属硅化物制成的薄膜。对这两种类型的膜的兴趣在于它们用于电子应用的功能特性。我们感兴趣的金属硅化物是用于制造先进的硅基集成电路中的电连接引线和栅极焊盘。对于器件尺寸低至几十纳米，需要对薄膜原子结构有详细的了解。有机薄膜在场效应晶体管和发光晶体管应用中用作有源半导体层。有机电子学的优点包括低制造成本、大面积和柔性衬底上的器件。在这些场效应器件中，器件性能依赖于有机半导体和栅极绝缘体之间的界面处的几个分子层中的分子的有序性，该界面是几纳米厚度的区域。我们的研究是表征感兴趣的这些纳米尺度区域中的原子或分子结构，并基于结构理解来改进成膜过程以获得所需的功能特性。我们研究这些纳米薄膜的主要工具是各种波长的X射线，由加拿大光源的同步加速器产生。我们还在美国使用高级光子源，使用加拿大机构参与的太平洋西北联盟设施。在实验上，我们使用了一种组合的方法，包括X射线吸收光谱（扩展的X射线吸收精细结构和近边X射线吸收精细结构），掠入射X衍射和X射线散射技术来探测纳米结构。金属硅化物薄膜由我们的合作者通过固态反应形成。有机半导体薄膜是在我们的实验室在圭尔夫使用真空气相沉积技术，辅助原子力显微镜成像技术，以确保其化学成分的完整性的样品和光电子能谱技术的形态完整性。

The proposed research is about the structure-function relationship of two types of thin films: one is made of organic semiconducting molecules and the other is made of metal silicide. The interest in both types of films lies in their functional properties for electronic applications. The metal silicides of our interest are for making electrical connection leads and gate pads in the advanced silicon-based integrated circuits. For device dimensions down to several dozen nanometers, a detail understandings of the film atomic structures is required. The organic thin films are used as active semiconductor layers in field-effect transistor and light emitting transistor applications. The advantages of organic electronics include low fabrication cost, large area and devices on flexible substrates. In these field effect devices the device performance relies on the orderliness of molecules in few molecular layers at the interface between organic semiconductor and gate insulator, a region of few nanometers in thickness. Our research is to characterize the atomic or molecular structures in these nanometer scale regions of interest, and base on the structural understanding to improve the film formation process towards the desired functional properties. Our primary tool for investigating these nanoscale films is X-rays of various wavelength, generated by the synchrotron accelerator at the Canadian Light Source. We also use the Advanced Photon Source in the States, using the pacific northwest consortium facilities participated by Canadian institutions. Experimentally we use a combined approach including X-ray absorption spectroscopy (extended X-ray absorption fine structure and near edge X-ray absorption fine structure), grazing-incidence X-diffraction and X-ray scattering techniques to probe the nanoscale structures. The metal silicide films are formed by solid state reactions by our collaborators. The organic semiconductor films are fabricated in our laboratories at Guelph using vacuum vapor deposition techniques, assisted with atomic force microscope imaging techniques to ensure the morphological integrity of the samples and photoelectron spectroscopy techniques for their chemical composition integrity.