Nanoscale space charge generation in local oxidation nanolithography
Marco Chiesa from the IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC) Isaac Newton 8, PTM, E-28760 Tres Cantos, Madrid, Spain, talks about his poster: Nanoscale space charge generation in local oxidation nanolithography
Abstract: We have measured the surface potential and the space charge generated during the first stages of field-induced atomic force microscopy oxidation. In humid air, the surface potential can be either positive or negative. However, in dry atmosphere, the surface potential is always negative. The discrepancy is attributed to a screening effect of the water molecules. These results indicate that a negative space charge with a density of about 1017 cm-3 is present in the oxide for oxidation times below 10 ms. Such charge, which does not exclude the presence of cations at the metal/oxide interface, is likely to take the form of unreacted oxyanions. These results explain and support the use of local oxidation patterns templates for building molecular architectures based on electrostatic interactions. They also establish the space charge build-up as an intrinsic feature in local oxidation experiments.