【作者】 牛新军；

【导师】 张玉明；

【作者基本信息】 西安电子科技大学 ， 微电子学与固体电子学， 2002， 硕士

【摘要】 4H-SiC MPS是很有前途的半导体功率整流器。本文对4H-SiC MPS的工作机理进行了模拟分析，优化设计了器件结构，并对其功率损耗特性进行了研究。 模拟了4H-SiC MPS的输运特性，对其工作机理进行了二维分析。通过对器件体内各物理量的定量分析，得出PN结对肖特基的作用是通过其耗尽层和两PN结之间的间隙来影响肖特基的导电沟道这一结论。MPS结构的应用，在保留SBD正向特性的同时，大大提高了其反向特性，而碳化硅材料的应用更加强化了MPS的这一优势。 提出了一种新的4H-SiC MPS解析模型。基于此模型，提出在对正反向特性进行折衷时，如何选择合适的外延层掺杂浓度和厚度、肖特基接触和PN结网格宽度、PN结深度和掺杂浓度。通过对4H-SiC MPS击穿特性的二维模拟，提出如何选择合适的PN结深度、外延层掺杂浓度和厚度以及如何运用JTE终端技术来提高击穿电压。 建立了4H-SiC MPS的功率损耗的解析模型并对其功率损耗特性进行了计算。提出从功耗的角度考虑，4H-SiC MPS存在一个最佳工作温度。本文中所研究的4H-SiC MPS在770K左右具有最低的功耗。更多还原

【Abstract】 4H-SiC MPS is a promising power semiconductor rectifier. The working mechanics, optimum design and power dissipation was studied in this thesis.The transport characteristics of 4H-SiC MPS was simulated. The working mechanics of 4H-SiC MPS was two-dimensional analyzed. According to the analysis of physical quantities in the body, we got a conclusion that the effect of PN junction on Schottky is through its depletion layer and the gap between two PN junctions. The application of MPS structure improves the reverse characteristics and preserves the forward characteristics of SBD. And the application of Silicon carbide enhances the advantage of MPS structure.A analytical model of 4H-SiC MPS was given. Based on this model, it was presented that how to select the thickness of epilayer, the doping concentration of epilayer, Schottky contact, the width of PN grid, the depth of PN junction and the doping concentration of PN junction for the trade-off between forward and reverse characteristics. It also put forward that how to select appropriate epilayer doping concentration and thickness, PN junction depth and JTE technology to increase the breakdown voltage of 4H-SiC MPS.A power dissipation model of 4H-SiC MPS was established. The power dissipation of 4H-SiC MPS was calculated. The influences of temperature on SiC mobility, ionization rate and intrinsic carriers density were taken into account. We found that the 4H-SiC MPS has an optimal work temperature. For the MPS mentioned in this paper, the lowest power dissipation emerges at about 770K.更多还原