Phase Change Liner Stressor for Strain Engineering of P-Channel FinFETs

A novel Ge₂Sb₂Te₅ (GST) liner stressor for enhancing the drive current in p-channel FinFETs (p-FinFETs) is demonstrated. When amorphous GST changes phase to crystalline GST (c-GST), the GST material contracts. This phenomenon is exploited for strain engineering of p-FinFETs. A GST liner stressor wrapping a p-FinFET can be shrunk or contracted to generate very high channel stress for drive current enhancement. Saturation drain current enhancement of ~80% and linear drain current enhancement of ~110% are observed for FinFETs with c-GST liner stressor over the control or unstrained FinFETs. The drain current enhancement is higher for 0° rotated FinFETs as compared with that of the FinFETs with 45° rotation, due to the orientation-dependent piezoresistance coefficients. The drain current enhancement increases with decreasing gate length. GST liner stressor could be a strain engineering option in sub-20-nm technology nodes.