40results about How to "Good ferroelectric properties" patented technology

A semiconductor memory device includes: a capacitor formed on a substrate and including a lower electrode, a dielectric film and an upper electrode; a selection transistor formed at the substrate; an electrically conductive plug for providing electrical connection between the selection transistor and the capacitor; and a diffusion barrier film provided between the electrically conductive plug and the lower electrode of the capacitor. The diffusion barrier film is a TaxSi1-xNy film or a HfxSi1-xNy film (where 0.2<x<1 and 0<y<1). The lower electrode includes an Ir film and an IrO2 film which are sequentially formed.

It is an object to provide a liquid composition for forming a thin film, with which a ferroelectric thin film having excellent characteristics can be prepared even by baking at a low temperature, and a process for producing a ferroelectric thin film using it. The above object is achieved by use of a liquid composition for forming a ferroelectric thin film, characterized in that in a liquid medium, ferroelectric oxide particles being plate or needle crystals, which are represented by the formula ABO₃ (wherein A is at least one member selected from the group consisting of Ba²⁺, Sr²⁺, Ca²⁺, Pb²⁺, La²⁺, K⁺ and Na⁺, and B is at least one member selected from the group consisting of Ti⁴⁺, Zr⁴⁺, Nb⁵⁺, Ta⁵⁺ and Fe³⁺) and have a Perovskite structure and which have an average primary particle size of at most 100 nm and an aspect ratio of at least 2, are dispersed, and a soluble metal compound which forms a ferroelectric oxide by heating, is dissolved.

Disclosed herein are a ferroelectric material that can be effectively used in manufacturing various electric and electronic elements, and a method of forming a ferroelectric layer using the ferroelectric material. The ferroelectric material in accordance with the present invention is composed of a mixture of an inorganic ferroelectric material and an organic ferroelectric material. The method of forming a ferroelectric layer includes: preparing a mixed solution of an inorganic ferroelectric material and an organic material; forming a ferroelectric film by applying the mixed solution onto a substrate; and forming a ferroelectric layer by annealing the ferroelectric film.

The invention provides a ferroelectric field effect transistor and a preparation method thereof. The ferroelectric field effect transistor includes a substrate, a source/drain, a gate stack, and sidewalls. The gate stack is composed of a gate dielectric layer, a lower electrode layer, a ferroelectric layer, an insulating dielectric layer, and a gate electrode stacked sequentially in a direction away from the substrate. Since the lower electrode and the ferroelectric layer of the ferroelectric field effect transistor are separated from the gate electrode through the insulating dielectric layer,the purpose of improving the ferroelectric characteristics of the ferroelectric layer and reducing the leakage between the lower electrode and the gate electrode can be achieved. The device operatingcharacteristics are improved and the proper operation of the ferroelectric field effect transistor can be ensured.

The present invention discloses preparation process of boron strontium titanate (BST) film material. The preparation process includes the first magnetically controlled DC sputtering to prepare Pt/Ti bottom electrode, pre-sputtering BaxSr1-xTiO3 ceramic target material with magnetically controlled RF sputtering apparatus to form BST film, slow heat treatment in O2 atmosphere and repeating the foregoing steps for three times; and final magnetically controlled DC sputtering to prepare upper electrode on the BST film so as to obtain sandwiched material. The said process can obtain ferroelectric BST film with high ferroelectric performance in perovskite structure and homogeneous crystal particle size. The ferroelectric BST film may be used in DRAM, dielectric phase shifter, voltage controlled filter, pyroelectric IR detector and other fields.

The present invention provides a liquid composition for forming a thin film, with which a ferroelectric thin film having excellent characteristics can be prepared even by baking at a low temperature, and a process for producing a ferroelectric thin film using it. A liquid composition for forming a ferroelectric thin film is used, which is characterized by comprising a liquid medium, crystalline ferroelectric oxide particles represented by the formula (Bi₂O₂)²⁺(Bi_m-1Ti_mO_3.5m-0.5)²⁻ (wherein m is an integer of from 1 to 5) or (Bi₂O₂)²⁺(A_m-1Ti_mO_3.5m-0.5)²⁻ (wherein A is Bi³⁺ or La³⁺, the La³⁺/Bi³⁺ ratio is from 0.05 to 0.5, and m is an integer of from 1 to 5) and having an average primary particle diameter of at most 100 nm, dispersed in the liquid medium, and a soluble metal compound capable of forming a ferroelectric oxide by heating, dissolved in the liquid medium.

The invention relates to the field of information storage thin-film material, disclosing an A-bit Pr doped BTO thin-film material which consists of praseodymium, bismuth, titanium and oxygen ions. The composition molecular formula of the material is Bi(4-11x/9)Pr<x>Ti3O12, and x is 0.3-0.9. The thin-film material is prepared by an RF magnetron sputtering method, which specifically comprises the following steps: depositing Bi(4-11x/9)Pr<x>Ti3O12 target on a Pt/TiO2/SiO2/p-Si substrate, pumping the target to microvacuum, carrying out pre-sputtering, inletting oxygen and argon to regulate working air pressure, re-sputtering, and finally annealing rapidly to obtain the thin film. The thin film prepared by the invention is the polycrystal thin film with random orientation, which has smooth surface, even grain size, low drain current and better ferroelectric hysteresis, thus being compatible with the existing CMOS process.

A method for manufacturing a ferroelectric memory includes the steps of: preparing a sol-gel solution; removing solvent from the sol-gel solution to obtain powder; dividing the powder into at least first powder and second powder; obtaining solution with the first powder; coating the solution on a first conductive film; and applying heat treatment to the solution on the first conductive film to form a ferroelectric film.

The invention relates to acid bismuth ceramic with multiferroic holmium and chrome codoping iron at room temperature and a preparation method of the acid bismuth ceramic, and belongs to the field of electronic ceramic materials. The ceramic has the chemical formula as follows: Bi1 - xHoxFe1- yCryO3, wherein x is greater than 0 and is less than or equal to 0.15, and y is greater than 0 and is less than or equal to 0.1. The method comprises the following steps: carrying out the treatments of mixing and ball-milling on raw materials including Ho2O3, Bi2O3, Cr2O3 and Fe2O3 by weight to obtain a slurry material; calcining for 2 hours at the temperature of 750 to 830 DEG C after the slurry material is dried; carrying out the ball-milling treatment on the powder again; adding a polyvinyl alcohol aqueous solution to the powder after the powder is dried; pressing the mixture into a tablet shape by using a tablet press under the pressure of 100 to 150 MPa; extracting colloid from a tablet-shaped material for 4 hours at the temperature of 550 DEG C; and finally, sintering the tablet-shaped material into the ceramic at the temperature of 800 to 870 DEG C. The multiferroic ceramic provided by the invention has excellent ferroelectric and ferromagnetic properties at the room temperature.

The invention relates to a method for preparing a BTS film by virtue of radio frequency magnetron sputtering. The method comprises the following steps: (1) firstly injecting ITO powder into a mold, rolling out, sealing the mold, and carrying out compression shaping; (2) putting target materials prepared in the step (1) and a substrate with a heat-conducting property into a vacuum sputtering cavity; (3) supplying oxygen and argon into the vacuum sputtering cavity, regulating the flow ratio of the oxygen and the argon to (12-18) to (2-8), regulating the intervals of the target materials to 8mm, setting the film plating power to 150w-175w, setting the film plating time to 3-4 hours, setting the sputtering pressure to 1.0Pa-1.5Pa, and setting the heating temperature of substrate to 200-400 DEG C; and (4) after the sputtering is finished, annealing the film-plated substrate, so as to obtain the film. According to the method, the film is prepared from powder target materials, so that the preparation cost of the BTS film is greatly lowered, and a sample prepared based on the process foundation has good structural performance and visible light permeability and excellent electrical performance.

The invention discloses a phenanthroline copper malonate ferroelectric functional material and a preparation method thereof. The ferroelectric functional material has a molecular formula of [Cu3(C12H8N2)3(H2O)2(C3H2O4)3].11H2O, is blue powder of which the purity is not lower than 99%, and has a C2 polarity point group structure. The ferroelectric characteristic parameters of the ferroelectric functional material are as follows: the remanent polarization strength 2Pr is equal to 0.09 muC.cm<-2>, the coercive electric field 2Ec is equal to 1.40kv.cm<-1>, and the saturation polarization strength Ps is equal to 0.39 muC.cm<-2>; and the cell parameter of the powder of the ferroelectric functional material is as follows: the saturation polarization strength of the ferroelectric functional material is 1.56 times that of Rochelle salt, so that the ferroelectric functional material is a new ferroelectric with excellent ferroelectric performance. The ferroelectric functional material is prepared by reacting a cupric salt solution with a methane dicarboxylic acid solution at first, then reacting with a phenanthroline solution and carrying out crystallization under the condition that the pH value is 3.0-5.0, has the advantages of less flow, simple process, low requirements for equipment, no pollution and low cost, and is easy to realize industrialization.

The invention discloses a tartaric acid terbium ferroelectric functional material, which is 100-mesh white tetragonal crystal system powder, and has a molecular formula of [Tb(H2O)3(C4H5O6) (C4H4O6)], a P41 space group structure, an electric hysteresis 2Ec value of 44.3kV . cm-1, 2, a Pr value of 1.60muC . cm-2, a Ps value of 0.176muC . cm-2, and better ferroelectric properties. A preparation method of the ferroelectric functional material is characterized in that: a terbium salt and a tartaric acid are synthesized into the high-purity tartaric acid terbium ferroelectric functional material by a soft synthesis method in coordination chemistry, and the better nucleation and growth of tartaric acid terbium crystals can be realized by controlling the concentration and ratio of the material, the pH value of a solution to 2 to 5, and the temperature of nucleation and growth of the crystal to 30-60 DEG C and the like. The method provided by the invention has the advantages of few flow, simple process, low equipment requirements, cheap terbium salt and tartaric acid as raw materials, no pollution, low cost, and easiness in industrialization.

The invention discloses a hydrated L-tartaric acid neodymium sulfate ferroelectric functional material and a preparation method thereof. The ferroelectric functional material has a molecular formula of {Nd2(H2O)2(L-C4H4O6)2(SO4)}.4H2O. The ferroelectric functional material has the following ferroelectric characteristic parameters: the remanent polarization 2Pr is 0.390 mu C/cm<2>; the coercive electric field 2Ec is 74.7 kv/cm; and the saturation polarization Ps is 0.307 mu C/cm<2>. The saturation polarization of the ferroelectric functional material is 1.23 times that of seignette salt, so that the ferroelectric functional material disclosed by the invention is a novel ferroelectric body with excellent ferroelectric performance. The preparation method comprises the following steps: carrying out a solvothermal reaction between neodymium oxide and L-tartaric acid by using an ethanol solvent; and adding a sulfuric acid solution into the mixture and nucleating in a reaction kettle so as to grow into the hydrated L-tartaric acid neodymium sulfate. The preparation method has the advantages of short flow, simple process, low equipment requirement, no pollution and low cost and can be easily industrialized.

The invention belongs to the field of ferroelectric function crystal materials, and particularly relates to a preparing technology of a bismuth-layer-structure K0.5Bi4.5Ti4O15 crystal. The preparing technology includes the steps that a polycrystal material is prepared; the polycrystal material is pulverized to be pressed a solid block again, the solid block is subjected to secondary sintering, polished and cut, and a polycrystal raw material rod is obtained; the polycrystal raw material rod is put at the lower portion of a hollow platinum tube, then put into a crystal growing furnace, heated in the argon atmosphere and melted, a platinum wire is led, and nucleation and growth of the crystal are carried out; the crystal completely grows to be slowly moved away fusion intervals, the platinum wire is taken out after stabilization is carried out for 1 h to 2 h, and bismuth-layer-structure K0.5Bi4.5Ti4O15 crystal is obtained; the bismuth-layer-structure K0.5Bi4.5Ti4O15 crystal is annealed at the high temperature. The K0.5Bi4.5Ti4O15 crystal prepared with the technology is good in evenness, and has the good ferroelectric characteristics.

A method for manufacturing a ferroelectric capacitor, includes the steps of: forming a ferroelectric capacitor layer having a lower electrode layer, a ferroelectric layer and an upper electrode layer on a base substrate; forming a titanium oxide layer on the ferroelectric capacitor layer; patterning the titanium oxide layer by high-temperature etching between 200° C. and 500° C. to thereby form a mask pattern; and etching the ferroelectric capacitor layer by using the mask pattern as a mask, to thereby form a ferroelectric capacitor having a lower electrode, a ferroelectric film and an upper electrode.

A ferroelectric capacitor with a ferroelectric film having a relatively larger amount of titanium constituent than zirconate constituent improves ferroelectric characteristics. The method for fabricating the ferroelectric capacitor includes the step of performing a heat treatment in an oxygen atmosphere after forming a contact opening in an insulating layer which covers an already formed ferroelectric capacitor. This heat treatment in an oxygen atmosphere can minimize undesirable side effects resulting from a platinum electrode oxidizing the ferroelectric film components.