PURPOSE: To inexpensively improve an information density by forming an information recording layer consisting of the thin film of an amorphous ferroelectric substance which is formed with electrodes on both surfaces and has a hysteresis characteristic on a light transmissive substrate having a specific thickness.
CONSTITUTION: The electrode 3 consisting of a light transmissive conductive thin film is formed on the light transmissive substrate 2 having ≥0.1mm thickness. The thin film 1 of the amorphous ferroelectric substance, such as thin film of an Fe2O3-Bi2O-PhTiO3 system, is formed by an RF sputtering method, etc., on this film 3. Further, the electrode 4 is formed of the thin film of Al on the film 1. The writing of the information is executed by impressing a forward electric field between the electrodes 3 and 4 to unify and saturate the polarization in the same direction, then removing the impressed electric field. A digital value '0' is then written as a residual polarization. A digital value '1' is written by impressing the electric field of an opposite direction at the electric field intensity at which the polarization inverts or below and irradiating one point of the electrode 3 with a laser beam to change the state of a hysteresis loop. The information is stored at the high density by this constitution.
| JP2005050403 | SEMICONDUCTOR STORAGE DEVICE |
| JPH11273360 | FERROELECTRIC STORAGE DEVICE |
| WO/2016/196835 | FERROELECTRIC MEMORY EXPANSION FOR FIRMWARE UPDATES |
KASHIMA ATSUSHI
FUJII KAZUHIRO
OKAMOTO IWAO
FUTAI HIROYUKI
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