Real-time evolution of trapped charge in a SiO2 layer: An electrostatic force microscopy study

Time-dependent motion of localized electrons and holes trapped in a SiO2 la yer is visualized with electrostatic force microscopy. Both negative and po sitive charges of up to similar to 10(10) e/cm(2) are trapped at a SiO2-Si interface in similar to 500-nm-diam area with a voltage stress between the tip and the sample. There is a higher probability for trapped charges to sp read out in the plane direction than to de-trap toward the Si substrate. Th e dynamics is explained with diffusion and drift of the charges induced by Coulombic interaction. (C) 2001 American Institute of Physics.