Patent ID: 7268411

Claim:
An electronic device capable to operate as a capacitor, comprising: a first electrode; an insulating film provided on the first electrode, including: n (n being an integer larger than 1) layers of barrier layers each consisting of a material having a bandgap larger than a first bandgap and having a relative permittivity smaller than a first relative permittivity; and (n− 1 ) layers of well layers each consisting of a material having a bandgap smaller than the first bandgap and having a relative permittivity larger than the first relative permittivity, each of the barrier layers and each of the well layers being stacked by turns, discrete energy levels being formed in each of the well layers by a quantum effect, thicknesses of the n layers of the barrier layers being not smaller than 2.5 angstroms, and a thickness dm (angstrom) (m=1, 2, . . . n) and a relative permittivity εm (m=1, 2, . . . n) of an m-th barrier layer (m=1, 2, . . . n) satisfying the condition 2.5>(d 1 /ε 1 +d 2 /ε 2 +. . . +dn/εn); and a second electrode provided on the insulating film.