重掺衬底对硅外延过程中系统自掺杂的影响

The Effect of Heavily Doped Substrate on System Autodoping of Silicon Epitaxy

重掺衬底掺杂剂在硅外延过程中通过气相和固相扩散进入反应系统,不仅对当前反应产生自掺杂效应,而且还会对后续外延产生影响,即系统自掺杂效应。通过实验设计量化了不同衬底掺杂剂、不同衬底电阻率、不同外延厚度的系统自掺杂效应影响大小;确认了衬底系统自掺杂重的产品会对后续衬底系统自掺杂轻的产品外延电阻率有显著影响。给出了各种情况下去除外延系统自掺杂效应的最佳方案。

The unwanted dopant from heavily doped substrates through gas and solid phase diffusion adhered to the reactor system,which not only incorporated in current epitaxial silicon deposition,but also affected the subsequent epitaxial silicon deposition.That is the system autodoping.Through the experimental design,the influence of different substrate dopants,different substrate resistivity and thickness of epitaxial layers on the system autodoping effect is quantified,and it is confirmed that the products with heavy autodoping in the substrates will have a significant impact on the epitaxial resistivity of subsequent products with light autodoping substrates.Finally,the best scheme to remove the autodoping effect of epitaxial system is given.