Localization and characterization of ultra thin gate oxide breakdown regions

Nano-scale diodes were formed after intentional gate oxide breakdown of n+ –olysilicon/oxide/p+ –ubstrate MOS capacitors by Fowler-Nordheim constant current injection. The nano-scale diodes called diode-antifuses are created by the formation of a small link through the oxide between the n+ –oly and the p+ –ubstrate with the properties of a diode. In this paper we report a simple method to localize the antifuse in terms to characterize the broken down oxide area. The method is based on the use of the blue-UV light emission from hot carriers to expose a deposited layer of photo resist on the top of the structure. After developing the exposed resist, a hole is observed in the photo resist layer where the antifuse was formed. This method can be applied on a ULSI circuit under operation to fix the regions of hot carriers and characterize them easily, or to identify where output power is lost by the circuit in terms to improve its design.