功率器件用n/p型4H-SiC同时形成欧姆接触工艺

Processes of Simultaneous Formation of n/p-Type 4H-SiC Ohmic Contacts for Power Devices

综述了在n/p型4H-SiC上同时形成欧姆接触技术的研究进展,包括欧姆接触理论、欧姆接触工艺及其优缺点以及热稳定性/可靠性等方面。重点介绍了基于Ni基金属的n/p型4H-SiC同时形成欧姆接触的工艺,包括以金属Ni为基础并结合Ti和Al与W等金属所形成的各种复合接触材料、通过合适的合金化退火工艺后得到的合金相、形成欧姆接触后得到的比接触电阻率,讨论了可能的欧姆接触形成机理,评估了其热稳定性/可靠性。讨论了在工艺上增加保护层对Ni基n/p型4H-SiC欧姆接触的性能以及热稳定性/可靠性等性能的影响。最后,评估了该工艺的研发现状和存在的问题,并提出未来的展望。

The research progresses on simultaneous Ohmic contact formation on n/p-type 4 H-SiC are reviewed,including Ohmic contact theory,Ohmic contact processes and their advantages and disadvantages,and thermal stability/reliability,etc.The review focuses on Ni-based n/p-type 4 H-SiC simultaneous formation of Ohmic contact processes,including various composite contact materials based on Ni and with incorporation of other metals such as Ti,Al and W,their alloy phases obtained by various proper alloying anneal processes,and the specific contact resistivities got after forming Ohmic contacts.The possible mechanisms of forming Ohmic contacts are discussed,and the thermal stability/reliability are evaluated.The effects of additional protection layer on the performance and thermal stability/reliability of Ni-based n/p-type 4 H-SiC Ohmic contacts are discussed.In the end,the research and development statuses and existing problems of the process are evaluated,and the prospects are proposed.