To easily form a capacity variable element on a ceramic substrate at low cost by a method, wherein a dielectric film is formed by partially substituting the titanium element of barium titanate of a dielectric thin film with zirconium, hafnium or both zirconium and hafnium, and the element capacity is changed by applying a voltage between a lower electrode and an upper electrode.
A capacitance variable element is composed by successively forming a lower electrode 2, a dielectric thin film 3 and an upper electrode 5 mainly on a substrate 1. At this point, the dielectric thin film 3 is a thin film, in which the titanium element of barium titanate or barium/strontium titanate is partially replaced with hafnium or both of zirconium and hafnium. Specifically, the thin film is set as Ba(ZrxTi1-x)O3 (0.05≤x≤0.3). It is preferable that this dielectric thin film 3 be formed through sol-gel method.
MASUDA YOSHIYUKI
SATO SAKIKO
OTANI NOBORU
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