3.3 kV 4H-SiC 準超接面金氧半場效電晶體與終端區結構設計

Abstract

在本篇論文中，將透過TCAD Sentaurus軟體進行3.3 kV 4H-SiC Quasi-SJ VD MOSFET主動區設計以及3.3 kV 4H-SiC VD MOSFET終端區設計。在3.3kV 4H-SiC Quasi-SJ VD MOSFET主動區設計中，符合國內半導體代工廠的製程限制，將磊晶層中加入3根浮動式P型結構。每一根浮動式P型結構加入後，對浮動式P型結構的濃度、光罩開口寬度以及元件磊晶厚度進行優化設計，並採用電流擴散層(Current Spreading Layer, CSL)及混合磊晶層的技術；優化設計後的3.3kV 4H-SiC Quasi-SJ VD MOSFET主動區，在逆向偏壓下，擁有相當好的電壓承受能力，維持一定的崩潰電壓值，且在順向導通部分，能夠擁有比Conventional 4H-SiC VD MOSFET更低的導通電阻值，特徵導通電阻為6.47 mΩ∙cm^2。 在3.3 kV 4H-SiC VD MOSFET終端區設計中，採用Double Zone JTE結構以及在JTE中加入P+ Rings結構，並進行優化。透過P+結構能使終端區結構在逆向偏壓下，電場分布均並向外延伸，提高耐壓能力。並加入外環設計，能提高在JTE劑量上偏差的50 %容忍度，使終端區結構的崩潰電壓值對JTE劑量變化不會有明顯大幅的下降。

In this thesis, the 3.3 kV 4H-SiC Quasi-SJ VD MOSFET cell region and the edge termination region are designed by using TCAD Sentaurus. In the 3.3 kV 4H-SiC Quasi-SJ VD MOSFET cell region, the three floating P structures are formed in the epitaxial layer, and optimized by adjusting width and doping concentration. Moreover, the current spreading layer and the multiple drift regions with doping concentrations are adopted in the structure. For the reverse characteristics, the 3.3 kV 4H-SiC Quasi-SJ VD MOSFET can withstand reverse voltage of 3.3 kV with low leakage current, achieving the target of this research. Additionally, for the forward characteristics, the structure owns lower on-resistance 6.47 mΩ∙cm^2 than that of a conventional 4H-SiC VD MOSFET. The double zone JTE structure and the P+ Rings structures are adopted in the 3.3 kV 4H-SiC VD MOSFET edge termination region. The P+ Rings structures in edge termination design can make electric field extend more widely and uniformly to increase the breakdown voltage, so that the highest BV is 3973 V. Furthermore, the JTE outer rings structure are adopted in the design, in order to increase JTE dose tolerance which ensures that the breakdown voltage of the edge termination can be maintained at same value in wider JTE dose range. The tolerance percentage increase 50 %.