Ionization-Assisted Deposition of Large Molecular Weight Organic Materials and its Mass Analysis

开发功能有机薄膜器件需要一种沉积高质量大分子量有机材料薄膜的新技术。在真空的清洁环境中形成薄膜的干法工艺对未来微器件的发展尤其有利。然而，传统的真空蒸发技术很难制备出具有高分子量的有机材料薄膜。本项目旨在通过开发一种新的工艺技术——电离辅助沉积来解决这一问题。重点从工艺技术的角度对高分子量有机薄膜进行研究。其战略主要分为两类；1. 有机分子的直接沉积；在沉积过程中伴随聚合过程形成的膜。后一类按聚合反应类型又细分为两种方法；逐步反应…更多的n和链式反应。在第一类中，我们已经沉积了几种单体材料，包括苝四羧基癸二醇和8-羟基喹啉铝。研究发现，电离辅助沉积方法可以有效地控制这些材料的半导体和发光性能。该技术可应用于有机发光二极管等薄膜器件的研制。聚四氟乙烯是一种高分子材料，采用电离辅助法直接沉积聚四氟乙烯。得到了分子取向可控、电绝缘性能提高的聚合物薄膜。第二类是单体源材料在衬底表面发生蒸发反应形成聚合物薄膜。通过两种共沉积单体的分步反应得到聚脲薄膜；二异氰酸酯和双哌啶。研究发现，电离辅助沉积可以通过衬底上的偏置电压和薄膜表面积累的离子电荷来控制薄膜形成过程中的偶极子取向。结果表明，在没有额外极化处理的情况下，沉积薄膜具有光学非线性和电光效应。一些乙烯基化合物通过链式反应在底物表面聚合。虽然简单的蒸发技术不能产生聚合物薄膜，但电离辅助沉积可以在沉积过程中激发分子，并通过离子电流和离子加速电压来控制聚合反应。沉积束的质量分析表明，可聚合分子在电离过程中容易形成碎片。少

A new technique of depositing high-quality thin films of large-molecular weight organic materials is required for the development of functional organic thin film devices. A dry process, that forms thin films in the clean environment of vacuum, is especially favorable for the future development of micro devices. However, it has been difficult by the conventional vacuum evaporation technique to produce thin films of organic materials that have high molecular weight. This project aims to solve this problem by developing a new process technique, ionization-assisted deposition. The emphasis is to study the high molecular weight organic thin films from the standpoint of process technology. Its strategy is largely classified in two categories ; 1. Direct deposition of organic molecules, and 2. Film formation that accompanies polymerization process in the course of deposition. The latter category is subdivided into two methods according to the type of polymerization reaction ; stepwise reactio … More n and chain reaction.In the first sategory, we have deposited several monomer materials, including perylenetetracarboxylicdianhidride and 8-hydroxyquinoline aluminum. It has been found that the ionization-assisted deposition method was effective in controlling the semiconducting and light emitting properties of these materials. The technique can be applied for the development of thin film devices such as organic light-emitting diode. As a polymeric material, direct deposition of polytetrafluoroethylene was deposited by the ionization-assisted method. Thin polymeric films that have controlled molecular orientation and improved electrical insulation capability were obtained.In the second category, monomer source materials were evaporated to form polymeric thin film by the reaction on the substrate surface. Polyurea thin films were obtained by stepwise reaction of two codeposited monomers ; diisocyanate and dipiperidine. It was found that the ionization-assisted deposition can control the dipole orientation during the film formation by means of the bias voltage on the substrate and the ionic charge accumulated on the film surface. As a consequence, the as-deposited films showed optical nonlinearity and electro-optic effect without additional poling process. Some vinyl compounds were polymerized by chain reaction on the substrate surface. Although the simple evaporation technique does not yield polymeric films, the ionization-assisted deposition can excite the molecules during the deposition and can control the polymerization reaction by the ion current and ion acceleration voltage. Mass analysis of the deposition beam showed that the polymerizable molecules easily form fragments upon the ionization process. Less