Capacitor materials

Updated March 26, 2006

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Materials for thin-film capacitors

Thin-film capacitors are single layer metal-insulator-metal (MIM) capacitors are formed by thin-film processes. Examples include most capacitors on MMICs. It is possible to form MIC capacitors on ceramic thin-films, but the rough surface of the ceramic means a world of hurt for yield (potential pin-holes) so we don't recommend it! Here's just a few dielectrics that are used in MIM caps:

Silicon nitride: Si₃N₄ dielectric constant 7.5 (used in most MMIC MIM caps)

BTW, the dielectric constant of silicon nitride can vary depending on how it is deposited. Consult your favorite foundry!

Silicon dioxide: SiO2 dielectric constant 4.5

Titanium dioxide: dielectric constant 96

Materials for ceramic capacitors

Barium titanate (very high but not stable...)

Ceramic capacitors formulas often use a mixture of barrium titanate for high dielctric constant

Titanium pentoxide (Ti2O5): 41

Niobium pentoxide (Ni2O5): 26

Titanium oxide

Calcium titanate

Aluminun dioxide (Al2O5): 9.8

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