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Thermal Capacitive Ferroelectric Storage Device

IP.com Disclosure Number: IPCOM000077779D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Jacobs, JT: AUTHOR [+3]

Abstract

High-speed switching is obtained in a data storage device comprising a memory element, having a ferroelectric region 5 in contact with a thermal capacitive region 4.

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Thermal Capacitive Ferroelectric Storage Device

High-speed switching is obtained in a data storage device comprising a memory element, having a ferroelectric region 5 in contact with a thermal capacitive region 4.

Ferroelectric region 5 stores binary states of polarization in a domain structure. Capacitive region 4 exhibits a very large increase in dielectric constant with a small increase in temperature, due to the dielectric anomaly as is shown in Fig. 2.

When energy such as laser thermal energy 6 is applied to the selected portion 7 of capacitive area 4 through transparent electrode 1, voltage Vc across capacitive region 7 reduces as a result of the increased capacitance arising from increased dielectric constant. As a constant voltage V with selected polarity is applied across electrodes 1 and 2, this causes voltage Vf across ferroelectric region 8 to increase. Voltage V and the applied energy are chosen to allow voltage Vf to exceed, when it is increased, voltage Vs which is the voltage required for the ferroelectric polarization reversal.

Thus, if the polarization was opposite the polarity of the applied polarization, that region is switched as shown in Fig. 1(c). If it was not opposite, no switching occurs. Reading of the state of polarization of the domain region is achieved by reading the current during the switching process or by optical polarization reading techniques.

It is also possible to heat capacitive region 7 to a temperature which causes ferroe...