Information recording medium in which information is recorded as irregularities, and method of manufacturing information recording medium
OwnerAtsushi Onoe, Takanori Maedainventors
Life of this patent
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Abstract
A ferroelectric thin film (11) is formed by using ferroelectric bodies having different etching rates in accordance with polarization direction and the ferroelectric thin film (11) is etched so as to form a pit (14) having a maximum length value of 1 nm to 30 nm in the orientation direction. Moreover, the depth of the pit (14) is set so that it is possible to distinguish the electrostatic capacity based on the polarization direction of the ferroelectric thin film (11) from the electrostatic capacity based on the pit (14).
Claims12
An information recording medium comprising:
- a ferroelectric thin film;
- an electrode layer disposed under said ferroelectric thin film;
- and
- a plurality of concave portions or a plurality of convex portions formed on an upper surface of said ferroelectric thin film,
- said plurality of concave portions or said plurality of convex portions being arranged so as to correspond to a bit arrangement of digital data,
- a minimum value of length in an arrangement direction per 1 bit of each of said concave portions or said convex portions being 1 nm or more but not exceeding 30 nm.
An information recording medium comprising:
- a ferroelectric thin film;
- an electrode layer disposed under said ferroelectric thin film;
- and
- a plurality of concave portions or a plurality of convex portions formed on an upper surface of said ferroelectric thin film,
- said plurality of concave portions or said plurality of convex portions being arranged so as to correspond to a bit arrangement of digital data,
- a depth of each of said concave portions or a height of each of said convex portions being set such that amount of change in capacitance of said ferroelectric thin film based on a polarization direction of said ferroelectric thin film is greater than that based on presence or absence of said concave portions or said convex portions.
A method of manufacturing an information recording medium in which information is recorded as physical concave portions or convex portions in a medium material, said method comprising:
- a voltage applying process of locally changing a polarization direction of a ferroelectric substance by preparing the medium material, which has a ferroelectric thin film and an electrode layer, the ferroelectric thin film being formed of the ferroelectric substance whose etching rate varies depending on a difference in the polarization direction and having an upper surface crossing the polarization direction of the ferroelectric substance, the electrode layer being jointed to a lower surface of the ferroelectric thin film, by bringing a tip of a probe close to or into contact with the upper surface, and by applying a voltage between the tip of the probe and the electrode layer;
- and
- an etching process of etching the upper surface by bringing the upper surface of the ferroelectric thin film of the medium material after said voltage applying process into contact with an etchant to thereby etch the upper surface.
Dependencies are inferred from the claim text.