Light switched plasma charging damage protection device allowing high field characterization

One of the main problems in Plasma Charging Damage (PCD) measurement is the need to reference the measured damage to a zero level. Especially when the reference device is small it can not be created damage free without a protective device parallel to the gate. Normally such a device does not allow destructive measurement involving high fields and both polarities. This paper describes a structure, which is capable of protecting a device from PCD, but at the same time allows bipolar high-field diagnostic stress after the end of the process. Its usefulness is demonstrated on a realistic PCD test structure.