Fabrication and characteristics of MOS-FET's incorporating anodic aluminum oxide in the gate structure

Anodic aluminum oxide films have been grown by means of a simple process which is compatible with the existing planar silicon IC fabrication technology. Device structures have been fabricated and tested in order to demonstrate the usefulness of anodized layers of evaporated aluminum in a multiple layer metallization scheme. Results of anodization of thin aluminum layers on a silicon substrate indicate complete conversion of aluminum into aluminum oxide and in addition, formation of a thin underlying layer of silicon dioxide. For the anodic aluminum oxide a growth rate of 11·5 Å/volt at a current density of 0·5 mA/cm² has been found to produce quite satisfactory quality of insulting layers. Experimental results are presented illustrating the C?V and I?V characteristics of p-channel MOS-FET's with both the partially anodized stacked-gate structure and the over-anodized double-oxide layer gate structure.