无铅掺杂银浆的激光烧结机理研究

The project proposes novel laser sintering technology, which achieves doping and sintering simultaneously to obtain heavy doped area and seed layer of gridlines. In addition, the environment-friendly lead-free doped silver paste is applied. The proposed project will study the distribution of recrystallized silver crystal grain by topological analysis method. By the adoption of topography optimization, the contact resistance can be reduced, through the relationship between microscopic topography and some factors, such as laser parameter, annealing and so on. The interface carrier transport mechanism will be confirmed and conductive mechanism will be explored by detailed analysis on several aspects, such as doping concentration distribution, phase analysis, electrical property and so on. The mechanism of laser-induced damage can be detailed analyzed at the micro-scale by information analysis of crystal imperfection. The microscopic mechanism of degree reduction of laser-induced damage by annealing technology will be investigated to reduce the damage degree. The finite difference methods is applied to describe the laser sintering process consisted of multiple steps, such as melting, doping, recrystallizing, sintering and so on. The diffusion behaviors of phosphorus atoms and silver atoms in liquid-phase silicon are researched, considering multi-aspect actual conditions, including crystal change, convection process, non-steady-state temperature distribution, crystal imperfection, phase state of boundary regions of solid-liquid phase and so on. The novel numerical model of diatomic liquid-phase diffusion will be established. By the investigation of this project, the mechanism of novel laser sintering technology can be verified and the scientific guidance can be provided for the specific implementation of proposed technology.

本项目提出了新型的激光烧结技术，能够一步完成掺杂和烧结两个技术环节，同时获得重掺杂发射区和栅线电极种子层，并采用环保型的无铅掺杂银浆。拟采用拓扑分析方法研究重结晶的银晶粒分布，通过微观形貌与激光参数、热退火等因素的关系，采用形貌优化降低接触电阻；通过掺杂浓度分布、物相分析、电性能等方面的深入分析，确立界面载流子输运机制，研究探索导电机理；通过晶体缺陷的信息分析，在微观尺度探讨研究激光诱导损伤机理，并研究热退火降低激光诱导损伤程度的微观机理，同时降低损伤程度；采用有限差分方法描述包括熔化、掺杂、重结晶、烧结等多环节的激光烧结过程，考虑晶型转变、对流过程、非稳态温度场分布、晶体缺陷、固相-液相交界区域的相态等多方面实际情况，研究磷原子和银原子在液体硅中的扩散行为，建立新型的双原子液相扩散数值模型。通过本项目的研究，能够探明新型激光烧结技术机理，从而为该技术的具体实施提供科学指导。

本项目提出了新型的激光烧结技术，能够一步完成掺杂和烧结两个技术环节，同时获得重掺杂发射区和栅线电极种子层，并采用了环保型的无铅掺杂银浆。采用拓扑分析方法研究重结晶的银晶粒分布，通过微观形貌与激光参数、热退火等因素的关系，采用形貌优化降低了接触电阻；通过掺杂浓度分布、物相分析、电性能等方面的深入分析，确立界面载流子输运机制，研究探索了导电机理；通过晶体缺陷的信息分析，在微观尺度探讨研究激光诱导损伤机理，并研究热退火降低激光诱导损伤程度的微观机理，同时降低损伤程度；采用有限差分方法描述包括熔化、掺杂、重结晶、烧结等多环节的激光烧结过程，考虑晶型转变、对流过程、非稳态温度场分布、晶体缺陷、固相-液相交界区域的相态等多方面实际情况，研究了磷原子和银原子在液体硅中的扩散行为，建立新型的双原子液相扩散数值模型。通过本项目的研究，能够探明新型激光烧结技术机理，从而为该技术的具体实施提供科学指导。