【作者】 廖晓明；

【导师】 冉均国；

【作者基本信息】 四川大学 ， 生物医学工程， 2006， 博士

【摘要】 金刚石具有一系列高质量辐射剂量计所需的物理化学性质,高温下工作性能稳定,抗辐射能力强,与人体组织相近的原子序数,能承受极高通量粒子辐照,加之金刚石无毒,与组织液不会发生化学反应,是理想的生物活体内置辐射剂量探测材料,是目前广泛应用的Si二极管和电离室辐射剂量计的理想替代品。因此开展CVD金刚石薄膜辐射剂量计的研究具有重要的理论意义和广阔的应用价值。在目前化学气相沉积(CVD)单晶膜和金刚石N型掺杂一直未取得突破性进展的情况下,如何获得高纯、高取向探测器级CVD金刚石薄膜来制作高性能CVD金刚石辐射剂量计成为该领域的热点和前沿研究课题之一。本文针对目前辐射剂量计存在灵敏度低和空间分辨率差、或耐辐射性不好、寿命短等问题,进行新型金刚石薄膜辐射剂量计的基础研究和设计。采用微波等离子体化学气相沉积(MWPCVD)装置,进行了形核、生长工艺对制备金刚石薄膜质量的影响,以及辐射剂量计金刚石薄膜的等离子体后处理研究,以获得高纯、高取向辐射剂量计金刚石薄膜;从分形的角度对金刚石薄膜表面进行了有关研究;进行了简单金刚石薄膜辐射剂量计器件的设计制作和基本性能测试;研究了金刚石薄膜组成、结构与电学性能、辐射响应性的关系;在此基础上作一些初步的机理分析,为后续的深入研究打下基础。本研究一方面通过金刚石粉手工研磨Si衬底表面和超声振荡清洗Si衬底的预处理方法,另一方面通过形核阶段结束后用纯氢等离子体刻蚀一段时间,以除去形核过程中形成的非金刚石相碳核,以及在形核结束后膜的正常生长过程中,每当膜生长一段时间后用纯氢等离子体作一定时间的刻蚀,来达到提高更多还原

【Abstract】 Diamond has a number of properties that make it a potentially remarkable material for use as a radiation dosimeter including high-temperature operation stability, high radiation hardness, the resistance to high irradiation fluxes and its tissue equivalence. In addition, the diamond is non-toxic and inert to tissue fluid, so it is suitable for in–vivo radiation detection. Up to now, single crystal diamond grown by CVD (chemical vapor deposition) and n-doped diamond have not been made a great breakthrough, therefore, the fabrication of high-performance radiation dosimeters based on diamond films with high phase-purity and high-degree preferential orientation has been one of the highlights.The aim of this study is to develop a new kind of radiation dosimeter based on diamond thin films to overcome drawbacks of the current widely used radiation dosimeters, such as low sensitivity, poor spatial resolution, low radiation hardness, short endurance and so on. In this paper, in order to obtain the diamond thin films with high purity and high-degree orientation, the influence of nucleation parameters, growth parameters and in-situ plasma post-treatments on the quality of diamond films was studied systematically using a bell-jar type MWPCVD (microwave plasma assisted chemical vapor deposition) setup. The surface morphology of diamond thin films was investigated by a fractal method. Radiation更多还原