Increased etch selectivity of SiNx over Si is required for the gate spacer formation in miniaturized MISFETs, especially in the FinFET. In this work, the selectivity of SiNx over Si is evaluated using a novel hydrofluorocarbon etch gas with a microwave excited high-density plasma. By using this novel etchant gas, a higher selectivity of SiNx over Si was obtained compared to CH3F. The etch rate of Si was suppressed due to the deposition of a hydrocarbon film on Si surface without O2 gas. It was found that the selectivity of SiNx over Si near the SiNx sidewall decreased compared that far from the SiNx sidewall. By using flow rates of more than 12 sccm of the novel CxHyFz gas, the gate spacer was formed without Si recess even after the SiNx was overetched for an equivalent thickness of 40 nm.
|Number of pages||9|
|Publication status||Published - 2014|
|Event||International Symposium on Silicon Compatible Materials, Processes, and Technologies for Advanced Integrated Circuits and Emerging Applications 4 - 225th ECS Meeting - Orlando, United States|
Duration: 2014 May 11 → 2014 May 15
ASJC Scopus subject areas