Radiation-induced depassivation of latent plasma damage

Plasma treatments are widely used in microelectronic industry, but they may
leave some residual passivated damage in the gate oxides at the end of the
processing. The plasma-induced damage can be amplified by metal
interconnects (antenna) attached to the gate during the plasma treatments.
Ionising radiation reactivates this latent damage, which produces enhanced
oxide charge and Si/SiO2 interface state density. Two CMOS technologies
have been investigated, with 5 and 7 nm gate oxides. Threshold voltage
shifts, transconductance decrease, and interface traps build-up are always
larger for plasma damaged devices than for reference devices.