683 results about "Ferroelectric thin films" patented technology

The invention relates to a system and a method for performing impact loading on a micro test piece and measuring dynamic mechanical property. The method comprises the following steps of: instantly accelerating a bullet by using an electromagnetic pulse launch technology and launching the bullet at high speed; transmitting a stretching stress wave generated by collision of the bullet to the micro test piece by using a separated Hopkinson bar technology so as to generate the impact loading on the micro test piece; recording strain data of an input bar and an output bar, and acquiring an enlarged surface dynamic deformation image of the micro test piece; analyzing and obtaining a stress strain curve of the micro test piece subjected to the impact loading having different strain rates; and analyzing the surface dynamic deformation image of the micro test piece and obtaining a distribution of a bidimensional displacement field and a strain field during dynamic impact loading of the micro test piece. By the system and the method, the problem of research on the dynamic mechanical property of a micro electro mechanical system (MEMS), and membrane materials such as piezoelectric thin films, ferroelectric thin films and the like is solved.

A method of improving the physical and/or electrical and/or magnetic properties of a thin film material formed on a substrate, wherein the properties of the thin film material are stress-dependent, by selectively applying force to the substrate during the film formation and/or thereafter during the cooling of the film in the case of a film formed at elevated temperature, to impose through the substrate an applied force condition opposing or enhancing the retention of stress in the product film. The method of the invention has particular utility in the formation of ferroelectric thin films which are grown at temperature above the Curie temperature, and which may be placed in tension during the cooling of the film to provide ferroelectric domains with polarization in the plane of the film.

A method for improving the stability of ferroelectric storage devices comprises: providing a ferroelectric storage medium including a film of ferroelectric material; and repeatedly applying a voltage to the film of ferroelectric material to improve the stability of polarized bits in the film of ferroelectric material. An apparatus that is used to perform the method is also provided.

Electrically tunable electromagnetic bandgap (“TEBG”) structures using a ferroelectric thin film on a semiconductor substrate, tunable devices that include such a TEBG structure, such as a monolithic microwave integrated circuit (“MMIC”), and a method producing such a TEBG structure are disclosed. The present invention provides a semiconductive substrate having an oxide layer, a first conductive layer positioned on the oxide layer, a ferroelectric layer covering the first conductive layer, and a second conductive layer positioned on a surface of the tunable ferroelectric layer. The use of the ferroelectric layer, which have a DC electric field dependent permittivity, enables a small size, tunable EBG structure.

The invention belongs to the technical field of ferroelectric memory, in particular to a non-destructive readout ferroelectric memory and a manufacturing method and a read/write operation method thereof. The ferroelectric memory comprises a ferroelectric film layer and a read/write electrode layer which is arranged on the ferroelectric film layer, wherein a gap for partitioning the read/write electrode layer into at least two parts is formed in the read/write electrode layer; the polarization direction of the electric domain of the ferroelectric film layer is not basically parallel to the normal direction of the read/write electrode layer; read operation and write operation can be finished through the read/write electrode layer. The ferroelectric memory is simple in structure, is easiness to manufacture, is low in cost, and is suitable for high-density application; a non-destructive current readout way can be realized.

The invention belongs to the technical field of ferroelectric storage, and particularly relates to a ferroelectric nonvolatile memory and a preparation method and a read/write operation method thereof. The ferroelectric memory comprises a ferroelectric thin film layer, a ferroelectric storage unit etched on the surface of the ferroelectric thin film layer, and in-plane read/write electrode layers prepared at the left and right of the ferroelectric storage unit; and a polarization direction of an electric domain is basically not parallel to a normal direction of the read/write electrode layer. When an in-plane structure of the storage unit is changed, the multi-bit information storage can be realized. A read operation and a write operation can be completed by virtue of a storage unit left/right deposited read/write electrode layer etched on the surface, and an additional read electrode and an additional read/write electrode can be additionally arranged on the top of the etched ferroelectric storage unit so as to realize the read operation. The ferroelectric memory is simple in structure, simple in preparation, low in cost and capable of nondestructively and rapidly reading the stored electric-domain logic information in a large-current way.

A ferroelectric capacitor includes: a ferroelectric film, and a lower electrode and an upper electrode interposing the ferroelectric film, wherein the ferroelectric film includes a first ferroelectric layer of ferroelectric material having a perovskite type crystal structure expressed by a general formula ABO₃ formed by a metal organic chemical vapor deposition method, a second ferroelectric layer of ferroelectric material in which a part of B site element in ferroelectric material having a perovskite type crystal structure expressed by a general formula ABO₃ is replaced with Nb, and a third ferroelectric layer of ferroelectric material having a perovskite type crystal structure expressed by a general formula ABO₃ formed by a sol-gel method, which are sequentially laminated from the side of the lower electrode.

The invention has for its objects to provide a multilayer thin film comprising a ferroelectric thin film preferentially (001) oriented on an Si substrate, its fabrication process, and an electron device. To attain these object, the invention provides a multilayer thin film formed on a substrate by epitaxial growth, which comprises a buffer layer comprising an oxide and a ferroelectric thin film, with a metal thin film and an oxide thin film formed in this order between the buffer layer and the ferroelectric thin film, its fabrication process, and an electron device.

A ferroelectric stacked-layer structure is fabricated by forming a first polycrystalline ferroelectric film on a polycrystalline or amorphous substrate, and after planarizing a surface of the first ferroelectric film, laminating on the first ferroelectric film a second thin ferroelectric film having the same crystalline structure as the first ferroelectric film. A field effect transistor or a ferroelectric capacitor includes the ferroelectric stacked-layer structure as a gate insulating film or a capacitor film.

A method of producing a device with a ferroelectric crystal thin film on a first substrate including the steps of providing a ferroelectric crystal, of irradiating a first surface of the ferroelectric crystal with ions so that a damaged layer is created underneath the first surface, of bonding a block of material including the first substrate to the ferroelectric crystal to create a bonded element, wherein an interface is formed between the first surface and a second surface of the block, and of heating the bonded element and separating it at the damaged layer, so that a ferroelectric crystal layer remains supported by the first substrate. By this method, very thin films—down to thicknesses of a fraction of a micrometer—of ferroelectric crystals may be fabricated without jeopardizing the monocrystalline structure.

It is an object of the present invention to control the crystal orientation of a ferroelectric thin film as dictated by the application of a ferroelectric thin film device. To accomplished the stated object, a bottom electrode containing at least iridium is formed over a surface preparation layer whose main component is zirconium oxide, and an ultra-thin titanium layer is laminated over the bottom electrode. An amorphous layer containing the elemental metal and elemental oxygen that constitute the ferroelectric is formed over the titanium layer, and a crystallized ferroelectric thin film is formed by heat treating this amorphous layer. If the thickness of the titanium layer is kept between 2 nm and 10 nm in the lamination thereof, the ferroelectric thin film will have a priority orientation of (100), and if it is kept between 10 nm and 20 nm, the ferroelectric thin film will have a priority orientation of (111).

On an insulating film on a surface of a substrate a lower electrode is formed, and on the lower electrode a ferroelectric film is formed at a temperature equal to or less than 450 degree centigrade, or at a temperature equal to or less than the Curie temperature of the ferroelectric film. Thereafter, on the ferroelectric film an upper electrode is formed, and after the upper electrode is formed, heat treatment is applied at a temperature higher than the deposition temperature or the Curie temperature. Thereby, a ferroelectric film having a particular crystal orientation is formed, and when heat treatment at a temperature higher than the deposition temperature or the Curie temperature is applied to transform once to a paraelectric phase, without altering a crystal structure, a ferroelectric phase can be obtained, and thereby a ferroelectric film aligned in the spontaneous polarization orientations of the respective domains can be obtained.

An improved method for depositing ferroelectric particles on a surface of a substrate to form films or stand-alone bodies. The improvement is based on electrophoretic deposition (EPD) of ferroelectric films by using a tri-functional phosphate ester additive having a concentration less than 10 volume percent in the EPD suspension, without the need for addition of a binder. The method includes preparation of the suspension by washing and dispersing ferroelectric particles, for example, commercially available PZT powder, in a polar solvent such as ethanol, followed by addition of the phosphate ester additive to the suspension, and an ultrasound treatment. The suspension is used in EPD of the ferroelectric particles on a prepared substrate. Following EPD, the green film is dried and sintered at high temperature. Visual and physical examination of stand alone and patterned PZT deposited films show excellent quality obtained in manufacturing a diversity of piezoelectric products, featuring exceptionally high green film uniformity, thickness distribution, and reproducibility to within +/-2 microns for 20 micrometer film thickness. The phosphate ester additive functions by improving stabilization and control of suspension characteristics and properties during the electrophoretic migration process, and by improving desired dimensions, characteristics, and electrical properties of the deposited green film. Thin or thick ferroelectric films, either as stand alone products, or formed on geometrically demanding patterned or non-patterned substrates are produced by using the method. The improved method is applicable to different ferroelectric particulate materials and to different substrates used for manufacturing piezoelectric elements and devices, in a cost effective manner.

The invention provides a method for preparing a piezoelectric-ferroelectric thin film, relating to the technical field of preparation of lead zirconate titanate ceramics and being realized by the steps of preparing a precursor solution, utilizing a PLD method to prepare a substrate and adopting a Sol-Gel method to prepare the piezoelectric-ferroelectric thin film on a PZT crystal seed layer. The invention utilizes a method combing PLD and Sol-Gel to prepare a PZT thick film, thus having strong applicability to different substrates; and the prepared PZT thick film has the obvious advantages of high preferred orientation, even crystal size and compact structure, and can be used for preparing a lead zirconate titanate thin film with the thickness of 3-6 microns, the residual polarization value Pr of 25-45 mu C/cm<2> and the coercive field Ec of 40-65 kV/cm. At the same time, the method in the invention has relative low cost, strong controllability of programs and high industrialized application value.

The invention belongs to the technical field of ferroelectric storage, and particularly relates to an in-plane reading/writing non-volatile ferroelectric memristor and a fabrication method and operation method thereof. The ferroelectric memristor comprises a ferroelectric thin film layer and reading/writing electrode pairs, wherein the reading/writing electrode pairs are arranged on a surface of the ferroelectric thin film layer, a gap between the reading/writing electrode pairs is an irregular pattern, the polarization direction of an electric domain of the ferroelectric thin film layer is not parallel to a normal direction of a reading/writing electrode plane, and different information can be stored with change of different writing voltages during writing voltage operation of a certain bias direction on the reading/writing electrode pairs. By the ferroelectric memristor, non-destructive reading in a current mode can be achieved with continuous change of the reading voltage, the ferroelectric memristor is suitable for high-density application, and moreover, the ferroelectric memristor is simple to fabricate and is low in cost.

The invention discloses a ferroelectric local field enhanced two-dimensional semiconductor photoelectric detector and a preparation method. The detector is characterized in that: the structure of the detector from top to bottom comprises a substrate, a two-dimensional semiconductor, a metal source and drain electrodes, a ferroelectric functional layer and a semi-transparent metal upper electrode in sequence. The preparation method of the detector comprises the steps: a transition-metal chalcogenide two-dimensional semiconductor is prepared on the substrate, an UV lithography or an electron-beam lithography is adopted and combines stripping technology to prepare a metal electrode serving as a source electrode and a drain electrode of a semiconductor channel, a ferroelectric thin film is prepared on the structure, a semi-transparent or transparent electrode is prepared on the ferroelectric thin film, so that a two-dimensional semiconductor detector structure is formed. The detector can make the two-dimensional semiconductor channel background carriers to be completely exhausted through using polarized ferroelectric materials, tiny voltage is applied between the source electrode and the drain electrode, and photoelectric detection is realized through detecting the current signal change under light. The detector has advantages of high sensitivity, fast response, good stability, low power consumption, wide spectrum detection and the like.

A method of assembling arrays of small particles or molecules using an atomic force microscope to define ferroelectric domains includes depositing a ferroelectric thin film upon a substrate forming workpiece, then using an atomic force microscope having a conductive, tip for generating a pattern on this thin film to define desired nano-circuit patterns. Next, exposure of this thin film to a solution containing chemical species which selectively adsorb or accumulate under the influence of electrophoretic forces in selected regions of this thin film.