We found a strong correlation between the layer porosity and electrical properties of a SiO 2 layer deposited by inductively coupled plasma chemical vapor deposition. At 50 C the SiO 2 layers have a double structure: a dense layer in contact with the substrate and a porous layer on top of it. The critical thickness at which voids appear depends on the deposition rate. Breakdown voltage and charge trapping performances of SiO 2 layers are very good if the thickness is below the critical value and deteriorate significantly in thicker, porous, layers. Layer porosity is absent when the sample is deposited at 250 C.
30 Jan 2012
Volume: 5 Issue: 2 Pages: 021103
Applied Physics Express