【摘要】 研究了Ni基n型SiC材料的欧姆接触的形成机理,认为合金化退火过程中形成的C空位(Vc)而导致的高载流子浓度层对欧姆接触的形成起了关键作用。给出了欧姆接触的能带结构图,提出比接触电阻ρC由ρC1和ρC2两部分构成。ρC1是Ni硅化物与其下在合金化退火过程中形成的高载流子浓度层间的比接触电阻,ρC2则由高载流子浓度层与原来SiC有源层之间载流子浓度差形成的势垒引入。该模型较好地解释了n型SiC欧姆接触的实验结果,并从衬底的掺杂水平、接触金属的选择、合金化退火的温度、时间、氛围等方面给出了工艺条件的改进建议。更多还原

【Abstract】 The mechanism of Ni based ohmic contacts to n-type SiC is studied.The creation of carbon vacancies(Vc)during high-temperature annealing in the near-interface region of the SiC allow increased electron to transport through the Schottky barrier,leading to ohmic behavior of the contact.According to the band structure of ohmic contact,the specific contact resistance ρC consists of two parts(ρC1 and ρC2).ρC1 occurs between the contact metal and its underlying highly doped semiconductor layer(NDC)after alloying.ρC2 is brought about by a barrier appeared due to the concentration difference between the NDC and ND in the SiC active layer.This model is used to explain the experiment results and to optimize the process of the ohmic contact to n-type SiC.更多还原