NOVEL PHENOMENON OF THE AL-1 WT-PERCENT-SI CONTACTS ON THE NF3/AR POST-ETCHING-TREATED N-SI SUBSTRATES

Abstract

Post-etching treatment (PET) using an in situ NF3/Ar low-energy plasma was reported to be efficient in removing the residual layer and defects caused by reactive ion etching (RIE) as well as producing a clean surface conventionally believed suitable for electrical contacts. However, the PET process was found to increase the contact resistance between Al-1 wt%Si and n+-Si substrate for the first time. It is attributed to the formation of p-type-like Si epitaxy on the n+-Si substrate and the lower effective surface donor concentration.