A comparison between plasma charging-damage and inductive-damage: Damage response to Fowler-Nordheim stress

This paper reports on the results of a study performed to compare the effects of charging damage and inductive damage to 0.5 μm n-channel MOSFETs arising from plasma etching at the gate-definition etch and metal-1 etch levels, respectively. The MOSFETs were fabricated on 200 mm p/p⁺ silicon wafers using a full CMOS process. The gate-definition etch step was performed using a chlorine-based chemistry and the metal etch step was done using a BCl₃/N₂/Cl₂ plasma. It is found that charging damage is electrically inactive after the full CMOS process flow; however, it is electrically activated by Fowler-Nordheim (F-N) stress when charging damage is clearly seen to correlate with the area of charging antenna in the device. Inductive damage, on the other hand, is seen to impact transistor parameters directly after the CMOS process and before the application of F-N stress. This is attributed to distinctly different mechanisms that are responsible for the creation of the two types of damage: charging damage arises from a dc current stress, whereas inductive damage is suggested to arise from ac current stress.