Conductive atomic force microscopy studies of thin SiO2 layer degradation

The dielectric degradation of ultrathin (∼2nm) silicon dioxide (SiO2) layers has been investigated by constant and ramped voltage stresses with the conductive atomic force microscopy (CAFM). CAFM imaging shows clearly the lateral degradation propagation and its saturation. Current-voltage characteristics, performed at nanometer scale, show the trap creation rate in function of the stress condition. The critical trap density has been found.