摘要 |
Corrosion of the aluminum electrode layer in thin-film capacitors is inhibited or prevented, so that the capacitors can be operated at higher AC voltages. The aluminum is alloyed with copper (or other metal of low specific resistance) from about 0.2% to about 8.0% (by weight), and with about 0.2% to about 3.0% of metal having a higher valence than aluminum, such as chromium, hafnium, manganese, titanium, and zirconium. Because of its low specific resistance and its ability to form precipitate compounds with aluminum, the copper serves as a vehicle to transport the high valence metals to the grain boundary of the aluminum. The presence within the alloy of a metal having a higher valence than aluminum is believed to capture free electrons and so prevent a positive shift in pH, thus inhibiting corrosion.
|