Impact of surface proximity gettering and nitrided oxide side-wall spacer by nitrogen implantation on sub-quarter micron CMOS LDD FETs

We propose an advanced sub-quarter micron CMOS process for ultra shallow junction and high reliability using new nitrogen implantation technique. Nitrogen atoms implanted into the source/drain for NMOSFETs and PMOSFETs can suppress impurity diffusion and leakage current, since not only nitrogen atoms can occupy the diffusion path of arsenic and boron atoms but also the secondary defects induced by nitrogen implantation can act as a surface proximity gettering site. Moreover, this technique can remarkably suppress the hot carrier degradation for CMOS LDD FETs, since the segregation of nitrogen at interface between the substrate and the side-wall SiO₂ can reduce the interface state generation under the side-wall spacer.