Reduction of silicon dioxide by aluminum in metal-oxide-semiconductor structures

The reduction of SiO2 by Al was studied in Al/SiO2/Si structures above 350 degrees C. It was found that Al displaces Si in the oxide, forming an Al-O compound with an Al:O concentration ratio between 1:1 and 1.3:1. In the reacted areas, less than 1 at. % Si is left in what was originally a pure SiO2 matrix. The activation energy for the reaction in a pyrogenic oxide is approximately 2 eV. The reaction was found to be responsible for electrical failure of diodes manufactured using Al/SiO2/Si technology. (C) 1996 American Institute of Physics.