用白光退火研究VLSI浅结工艺

A study of shallow PN junction technology for VLSI by rapid thermal annealing

研究了砷注入硅和砷通过SiO_2层注入硅的快速退火特性。给出了制备0.1—0.6μm的PN结最佳条件。用透射电子显微镜(TEM)观察了晶格损伤退火恢复过程,以及高密度缺陷演变过程,发现增加退火时间和靶加热注入均可大大降低注入层剩余缺陷密度。还研究了增强扩散效应,结果发现,随注入束流密度的增加,增强扩散系数明显增大。给出了As扩散系数与注入条件和退火条件的关系。进一步研究了注入及退火条件对PN结漏电流的影响。确定了如何将PN结建立在离子注入损伤区之外的条件。

The RTA properties of As implanted into Si and implanted through a SiO2 film into Si are studied. The fabrication of PN junction with a depth of 0.1-0.6μm has been optimized. The processes of lattice restoration and defect density change during RTA are observed by TEM. It is found that if longer annealing time and hot target implantation are used the residual defect density can be reduced greatly. The results show that diffusion coefficient is increased with increasing of ion flux. The relation of diffusion coef-ficient with annealing and implantation conditions are given. The influences of the above mentioned conditions on leakage current of PN junction have been studied. The condir tions for making PN junction located out of the radiation damaged region have been discussed.