53 results about "Ferroelectric semiconductors" patented technology

Ferroelectric semiconductor switching devices are provided, including field effect transistor (FET) devices having gate stack structures formed with a ferroelectric layer disposed between a gate contact and a thin conductive layer (“quantum conductive layer”) . The gate contact and ferroelectric layer serve to modulate an effective work function of the thin conductive layer. The thin conductive layer with the modulated work function is coupled to a semiconductor channel layer to modulate current flow through the semiconductor and achieve a steep sub-threshold slope.

A new form of a solid-state non-volatile memory cell is presented. The solid-state memory cell comprises a series of different layers of ferroelectric materials, semiconductors, ferroelectric semiconductors, metals, and ceramics, and oxides. The memory device stores information in the direction and magnitude of polarization of the ferroelectric layers. Additionally, a method is presented for storing multiple bits of information in a single memory cell by allowing partial polarization of a single ferroelectric layer and stacking of multiple ferroelectric functional units on top of each other. Additionally, a technique for reading and writing said memory cell is presented. Additionally, the memory cell design allows for the formation of Schottky barriers which act to improve functionality and increase resistance. Additionally, a method is presented for depositing textured lithium niobate thin films.

The invention provides a Ferro-RRAM, a method of operating the Ferro-RRAM, and a method of fabricating the Ferro-RRAM, and pertains to the technical field of memory. The Ferro-RRAM comprises an upper electrode, a lower electrode, and a ferroelectric semiconducting thin-film layer provided between the upper electrode and the lower electrode and serving as a storage function layer; wherein the ferroelectric semiconducting thin-film layer is operable to generate a diode conduction characteristic by ferroelectric domain reorientation, and is operable to modulate the diode conduction characteristic by variation of the ferroelectric domain orientation; the Ferro-RRAM stores information according to variation of modulation of the diode conduction characteristic. The Ferro-RRAM has such characteristics of being simple in structure and fabrication, non-destructive readout and nonvolatile storage.

The invention belongs to the field of ferroelectric film materials and relates to a method for preparing a plumbum magnesium niobate-plumbum titanate (PMN-PT) ferroelectric film. The method comprises the following steps of: firstly, preparing a PMN-PT ceramic target; secondly, cleaning a silicon (Si) substrate; thirdly, preparing a LaNiO3 conductive buffer layer; and finally, preparing the PMN-PT ferroelectric film. The method for preparing the PMN-PT ferroelectric film has the advantages of simple process, high repeatability, capacity of preparing the large-area PMN-PT film with pure perovskite structure preferred orientation on a cheap silicon substrate with an actual application value, compatibility with a Si integrated process, low preparation cost and contribution to mass production of devices. The prepared film has the advantages of high ferroelectric properties and suitability for ferroelectric-semiconductor integrated devices.

A ferroelectric semiconductor device of the present disclosure includes a substrate, a ferroelectric layer disposed on the substrate, an electric field control layer that is disposed on the ferroelectric layer and has a predetermined internal electric field formed without the application of an external electric power to alter the magnitude of a coercive electric field of the ferroelectric layer, and a gate electrode layer disposed on the electric field control layer.

The invention belongs to the technical field of information storage, and particularly relates to a polarized tuning ferroelectric film diode memory, which comprises a substrate, a film bottom electrode prepared through electron beam evaporation or magnetron sputtering, a bismuth ferrite film prepared through pulse laser deposition or magnetron sputtering and a top electrode in sequence. Due to the polar modulation diode current density of 5.4A/cm2, the novel bismuth ferrite film made of semiconductor material in the invention is very suitable for high-density information storage and application, and the stored information simultaneously has the advantages of non-volatile performance, fatigue resistance, radiation resistance and non-destructive reading function of the variable resistance memory. Therefore, the invention improves the programming/erasing speed (the picosecond level) of the non-volatile memory cell, and has broad development space and market potential.

A ferroelectric semiconductor device of the present disclosure includes a substrate having a channel structure, a trench pattern having a bottom surface and a sidewall surface in the channel structure, a dielectric layer disposed on the bottom surface and the sidewall surface of the trench pattern, and a gate electrode layer disposed on the dielectric layer. The dielectric layer includes a ferroelectric layer pattern and a non-ferroelectric layer pattern that are disposed along the sidewall surface of the trench pattern.

The invention relates to a preparation method of a LiNbO3/III nitride heterostructure ferroelectric semiconductor thin film, the metal organic chemical vapor deposition method is firstly adopted to grow AlN/AlGaN and other heterostructure materials on a (0001)-plane sapphire substrate as a buffer layer or a compound substrate; then the buffer layer adopts a high-purify 5N ferroelectric material as a target material, the pulsed laser deposition method is used to obtain a high-quality ferroelectric material thin film on the heterostructure buffer layer or the compound substrate; the vacuum of a growth cavity is controlled to be more than 10 Torr; the temperature of the substrate is increased to 300 to 900 DEG C, then high-purity oxygen is introduced into the cavity, the oxygen pressure is controlled at 5 to 90 Pa; the frequency of a laser is adjusted to be 5HZ, the energy is 300mJ, the target material is carried out the laser pre-sputtering in advance for 3 to 5 minutes, and the surface pollution of the substrate is cleaned; finally, the pulsed laser is focused on the target material, and a target source is opened to grow the LiNbO3/III nitride heterostructure ferroelectric semiconductor thin film on the heterostructure compound substrate.

The present invention provides a ferroelectric semiconductor memory device in which the potential of data read out from a normal cell is compared with the reference level of a reference cell so as to determine whether the readout data is the “H” data or the “L” data, wherein since the reference cell is in the relaxed state when reading out data from the normal cell for the first time, the reference cell is reset before reading out data from the normal cell. Then, data is read out from the normal cell, and then the reference cell is reset. In second and subsequent data read operations of reading out data from a normal cell of another address, the reference cell is in the reset state, whereby the reference level is the same between the first data read operation and the second or subsequent data read operation. Thus, the reference level is always kept at a predetermined constant level when data is read out from normal cells.

An embodiment of the present memory cell includes a first layer of a chosen conductivity type, and a second layer which includes ferroelectric semiconductor material of the opposite conductivity type, the layers forming a pn junction. The first layer may be a conjugated semiconductor polymer, or may also be of ferroelectric semiconductor material. The layers are provided between first and second electrodes. In another embodiment, a single layer of a composite of conjugated semiconductor polymer and ferroelectric semiconductor material is provided between first and second electrodes. The various embodiments may be part of a memory array.

Provided are a nonvolatile semiconductor memory device including ferroelectric semiconductor patterns in respective memory cells and methods of writing and reading data. The device includes a substrate; a plurality of first conductive lines disposed in or on the substrate; a plurality of second conductive lines disposed in or on the substrate and having a different height from the first conductive lines, wherein the second conductive lines intersect the first conductive lines, respectively, to define a plurality of intersection regions; and a plurality of memory cells disposed on the substrate. Herein, the memory cells include ferroelectric semiconductor patterns, respectively, which are disposed between the first conductive lines and the second conductive lines that define the intersection regions.

The invention provides a method for preparing a low-band gap ferroelectric photovoltaic film through pulsed laser deposition. The method particularly comprises the following steps of: taking Pt/Ti/SiO2/Si(100) as a substrate; cleaning for 10 minutes through an ultrasonic cleaner by sequentially using acetone, absolute ethyl alcohol and deionized water, wherein the working frequency of ultrasonic waves is 40 kHz; then blow-drying by using nitrogen, then immediately loading into a vacuum cavity, and determining the temperature of the substrate at 600-800 DEG C, the oxygen pressure of a vacuum chamber at 0-5 Pa, the energy of a laser pulse at 100-500 mJ and the frequency of the laser pulse at 1-20 Hz; ablating a ceramic target material to obtain a low-band gap film product. The method provided by the invention is a physical vapor deposition method, has the advantages of fewer selected raw materials, economy, no pollution, simple preparation process, convenience for operation and easiness for production, and opens up a fire-new way for developing a solar cell based on a ferroelectric semiconductor.

The invention discloses a heterosynapse electronic device based on a two-dimensional ferroelectric semiconductor and a preparation method of the heterosynapse electronic device. The heterosynapse electronic device comprises a supporting substrate, a back gate electrode, a dielectric layer, a source-drain electrode and a packaging layer which are sequentially stacked from bottom to top, the source and drain electrode comprises a source electrode and a drain electrode, a conducting channel is arranged between the source electrode and the drain electrode, and the conducting channel is made of a III2-VI3 type two-dimensional ferroelectric semiconductor material; the source electrode and the drain electrode are respectively connected with two ends of the conducting channel and form Schottky contact with a Van der Waals interface; and the preparation method comprises the steps of preparing the packaging layer h-BN and the graphene electrode, preparing a PVA dry-method transfer film, performing dry-method transfer on the graphene electrode, preparing the graphene source and drain electrode and preparing the metal extraction electrode. The invention provides a memristive transistor which takes a III2-VI3 two-dimensional ferroelectric semiconductor material as a conducting channel, and realizes a heterosynaptic electronic device for regulating and controlling synaptic weight by inputting from two ends of a source electrode, a drain electrode and a grid electrode.

Disclosed relates to an organic material for a ferroelectric semiconductor device, which can be effectively used as a dielectric material of the ferroelectric semiconductor device, such as PVDF, etc. The PVDF having four crystal structures of α, β, γ, and δ shows a good hysteresis characteristic in the crystal structure of β-phase. A PVDF thin film having a crystal structure of β-phase has excellent hysteresis characteristics that show a capacitance value is decreased with the increase of an applied voltage in about 0 to 1V and increased with the decrease of an applied voltage in about 0 to −1V. A ferroelectric organic material having a crystal structure of β-phase is used on a channel region (54) between source and drain regions (52 and 53) of a silicon substrate (51). As ferroelectric organic materials, polyvinylidene fluoride (PVDF), PVDF polymer, PVDF copolymer or PVDF terpolymer and, further, odd-numbered nylon, cyano-polymer and their polymer or copolymer, etc. may be used.

According to the III-VI group material (GaSe)-based interlayer slippage ferroelectric field effect transistor device, the characteristic that interlayer slippage is controlled by an electric field in the material to achieve polarization overturning is utilized, regulation and control over the Fermi level and the conductivity of a channel can be achieved, and compared with a traditional ferroelectric field effect transistor, the device has the advantages that the device is simple in structure and convenient to implement. According to the two-dimensional ultrathin ferroelectric, the size of the device can be remarkably reduced, an effective gate electric field is increased, and the voltage required by overturning or polarization can be further reduced, so that low-power-consumption storage can be realized. The novel ferroelectric field effect transistor device for regulating and controlling interlayer slippage by the external electric field provides a new platform for realizing high-performance ferroelectric storage and a high-integration-level storage chip.

The invention discloses an alpha-indium selenide two-dimensional photoelectric detector based on a transparent electrode, which comprises an alpha indium selenide two-dimensional ferroelectric semiconductor layer, a hafnium oxide dielectric layer and a doped silicon substrate which are sequentially distributed from top to bottom, the alpha-indium selenide two-dimensional ferroelectric semiconductor layer is provided with the transparent electrode, and the detector is small in size and low in cost. Photoelectric responsivity is high.

The invention discloses a method for improving the photoelectric property of a BLFO/ZnO heterojunction by utilizing ferroelectricity and piezoelectric optoelectronics effects and relates to the fieldof ferroelectric semiconductor heterojunction devices. A pulse bias voltage is applied to a BLFO/ZnO heterojunction device, ferroelectricity of the BLFO is called, the BLFO/ZnO heterojunction device calls the ferroelectricity of the BLFO, compressive strain is applied to the BLFO/ZnO heterojunction device to introduce a piezoelectric photoelectronic effect, a purpose of simultaneously calling ferroelectricity and piezoelectric photoelectronic effects is achieved, and the total driving force of current carriers is enhanced. The preparation method is advantaged in that the BLFO/ZnO heterojunction device is prepared by adopting a sol-gel method and a hydrothermal method, influence of the piezoelectric photoelectronic effect and the ferroelectric effect on the photovoltaic characteristics is researched, carrier transport operation is modulated by using a piezoelectric photoelectronic effect, an open-circuit voltage and a short-circuit current of the BLFO/ZnO heterojunction device are remarkably improved, external electric field polarization is introduced on the basis of compressive strain, the piezoelectric photoelectronic effect and ferroelectricity are called, the total driving forceof a heterojunction energy band structure and carriers is modulated, and therefore photoelectric performance of the heterojunction is improved.

An all-ferroelectric semiconductor PN junction thin film device comprises a substrate, a bottom electrode, an N-type ferroelectric layer, a P-type ferroelectric layer and a top electrode in sequence from bottom to top, or comprises the substrate, the bottom electrode, the P-type ferroelectric layer, the N-type ferroelectric layer and the top electrode. Wherein the N-type ferroelectric layer is made of an N-type ferroelectric material, and the P-type ferroelectric layer is made of a P-type ferroelectric material. The invention further provides a preparation method of the all-ferroelectric semiconductor PN junction thin film device. The all-ferroelectric semiconductor PN junction thin film device can be used for solving the problem of destructive reading of data in an existing ferroelectric memory, and meanwhile more excellent non-destructive reading of electricity and light on the ferroelectric polarization state is achieved.