Overlapping Schottky gate CCDs on GaAs formed by anodic oxidation

Overlapping metal-gate charge-coupled devices (CCDs) have been formed on gallium arsenide (GaAs) using an anodic oxidation process to form the thin electrical isolation layers between the charge transfer electrodes. The active regions of the CCDs were formed by through-the-cap implantation of silicon and rapid thermal annealing. Aluminum was used for the electrodes and the anodic growth was performed in a cell at constant current to a forming voltage of 50 volts. All electrodes formed Schottky barriers to the CCD channel and the anodically formed dielectric isolation thickness was about 60nm. Dynamic operation of the CCDs has been observed at 25MHz and the transfer inefficiencies have been found to be less than 10^-3.