利用旋涂掺杂工艺与激光退火技术制备高性能Ge器件的研究

发布时间：2019-01-10 21:27

【摘要】：由于硅集成电路器件的尺寸遵循着摩尔定律不断缩小,即将接近其物理极限,减小栅长以提高性能的方法已经无法继续,因此寻找新的材料、结构、工艺和原理才是集成电路继续发展的方向。与硅同为四族元素的锗材料,由于其具有的较高空穴迁移率,成为了未来集成电路发展的热门候选材料。基于上述原因,本课题选择锗作为衬底材料进行讨论和器件制备。首先讨论了两种最成熟的集成电路掺杂工艺:气相热扩散和离子注入,分析了这些工艺应用于锗基立体结构器件超浅掺杂的局限性,比较得出旋涂掺杂工艺的优势和可行性。在介绍旋涂掺杂工艺基本步骤和原理后,针对锗材料的特点和集成电路工艺的要求,进行了掺杂元素种类的筛选。提出了使用激光退火改善p-n结中杂质分布的设想并讨论其可行性。从扩散的基本原理出发,建立模型计算旋涂掺杂和激光退火得到的p-n结中杂质的分布,讨论了适当参数激光退火对掺杂元素分布可能产生的改善。设计了包含旋涂掺杂和激光退火的p-n结工艺,通过实验制备了热处理和激光退火的旋涂掺杂p-n结,得到的器件性能符合预期,而且经过激光退火的p-n结开关比增大了近一个数量级,证明了激光退火对p-n结特性的改善,通过p-n结势垒电容的测试和计算,证明了杂质分布符合本课题的理论分析。完成p-n结的制备后,又设计了锗基旋涂掺杂晶体管工艺,并制备出具有一定器件性能的样品,证明了旋涂掺杂和激光退火融入传统晶体管工艺的可能性,并通过分析器件制备过程中的问题,提出了改进方案,指导后续的实验和研究。
[Abstract]:Since the size of silicon integrated circuit devices follows Moore's law, the method of reducing gate length to improve performance has been unable to continue, so we are looking for new materials and structures. Technology and principle are the direction of IC's development. Because of its high hole mobility, germanium, which is the same as silicon, has become a hot candidate for the development of integrated circuits in the future. For the above reasons, germanium is chosen as substrate material for discussion and device fabrication. Firstly, two most mature integrated circuit doping processes, gas phase thermal diffusion and ion implantation, are discussed. The limitations of these processes in ultra-shallow doping of germanium based stereoscopic devices are analyzed, and the advantages and feasibility of spin-coating doping process are compared. After introducing the basic steps and principles of spin-coating doping process, according to the characteristics of germanium materials and the requirements of integrated circuit technology, the kinds of doping elements are selected. The idea of improving impurity distribution in p-n junction by laser annealing is proposed and its feasibility is discussed. Based on the basic principle of diffusion, a model was established to calculate the impurity distribution in p-n junctions obtained by spin-coating doping and laser annealing, and the possible improvement of doping element distribution by laser annealing with appropriate parameters was discussed. The p-n junction process including spin-coating doping and laser annealing is designed. The p-n junction with heat treatment and laser annealing is fabricated experimentally. The properties of the device are in line with the expectation. Moreover, the switching ratio of p-n junction annealed by laser increases by nearly one order of magnitude. It is proved that the properties of p-n junction are improved by laser annealing. The barrier capacitance of p-n junction is measured and calculated through the measurement and calculation of the barrier capacitance of p-n junction. It is proved that the impurity distribution accords with the theoretical analysis of this subject. After the preparation of p-n junction, germanium based spin-coating doped transistors were designed, and samples with certain device properties were prepared, which proved the possibility of spin-coating doping and laser annealing joining into the traditional transistor process. By analyzing the problems in device fabrication, an improved scheme is proposed to guide the subsequent experiments and research.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN303;TN32

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