Mechanisms for Junction Degradation of Advanced MOSFETs Induced by Plasma Processing

MOSFETs with high-k gate stack (HfAlO
_x
/SiO
₂
) and those with SiO
₂
showed characteristic degradation induced by Ar-based electron cyclotron resonance (ECR) plasma, i.e., the increase in off-state leakage current (I
_Off
). The measurements of all source-to-drain current paths in MOSFETs revealed that the leakage through S/D-body junction was dominant. For both cases of the high-k gate stack and SiO
₂
, n-MOSFETs receive more severe damage than p-MOSFETs. It was found that difference of the gate leakage between high-k gate stack and SiO
₂
impacts on the junction degradation. C-V measurement identified that a root cause of the leakage increase is attributed to plasma-induced defect generation in the junction region.