We have constructed a model for the temporal evolution of the anodic space-charge layer and of the current during anodic bonding. The analytical expressions obtained interpolate continuously between the short-time and longtime behaviour of the current. The short-term behaviour corresponds to growth of a negatively charged, cation depleted abrupt layer. We suppose that this layer grows until the electric field at the anode interface reaches a critical value, large enough to start pulling the less mobile negative ions towards the anode. We model this anion depleted layer is another abrupt layer, which is electrically neutral, and whose thickness also grows with time, keeping the electric field at the interface constant and equal to the critical value. These conditions completely specify a continuous solution for the whole time domain. We expect the results will be useful to the interpretation of experiments on glass-silicon anodic bonding.
