TW200527651A - Ferroelectric capacitor and ferroelectric device - Google Patents

Abstract

A ferroelectric capacitor and a ferroelectric device are provided. The ferroelectric capacitor is consisted of a first electrode layer, a second electrode layer, and a ferroelectric dielectric layer between the first electrode layer and the second electrode layer. Also, at least one of the material of the first electrode layer and the material of the second electrode layer is a conducting material. Due to the conducting material, an Ohmic electrode/ferroelectric interface is existed between at least one of the first electrode layer and the second electrode layer, and the ferroelectric dielectric layer for eliminating the Schottky barrier between at least one of the first electrode layer and the second electrode layer, and the ferroelectric dielectric layer.

Description

200527651

[Technical field to which the invention belongs] The present invention relates to a capacitor and a device using the same, and more particularly to a ferroelectric capacitor and a ferroelectric device using the ferroelectric capacitor. [Previous technology] With the development of the times, mobile electronic products are becoming more and more important, such as mobile phones, personal digital assistants (PDAs), digital cameras, etc., making non-volatile memory = increasing demand, currently common non-volatile memory There is a mask, read-only memory (Mask ROM), flash memory (Flash memory) exclusively. However, the mask-type read-only memory cannot change the memory content, so the use range is greatly limited. Although flash memory can arbitrarily change the storage valley, it has limited write times and read and write speeds much lower than dynamic random access memory (DRAM) and static random access memory (sraM). The demand for new types of memory with high frequency, high read / write speed, low power consumption and low operating voltage has gradually emerged. At present, new types of memory with this advantage include ferroelectric random access memory (FeRAM) and magnetic memory. (Magnetic Random Access Memory, MRAM), etc. The ferroelectric memory system is composed of a transistor and a ferroelectric capacitor, and the ferroelectric capacitor is a platinum electrode layer on the lower layer and a ferroelectric dielectric layer made of a lead zirconate titanate (PZT) material in the middle. It is composed of an upper platinum electrode layer. In addition, the electrode layer in the capacitor is electrically connected to the source / drain region of the transistor through the metal plug of the insulating layer, and the size of the ferroelectric memory signal is determined by the residual polarization value in the ferroelectric capacitor.

13095twf.ptd Page 8 200527651 V. Description of the invention (2) The size, so how to increase the size of the residual polarization value is very important. In the above ferroelectric valley device, the work function of the 'starting electrode layer and the ferroelectric dielectric layer is very different, so when the two films are combined, the electrons in the ferroelectric dielectric layer having a small work function are combined. It will flow to the platinum electrode layer with a large work function until the Fermi Energy of each other is the same, so a Schottky Barrier will be generated at the interface of the two film layers, resulting in Figure 1 The phenomenon of band banding at the interface between the platinum electrode layer 10 and the ferroelectric dielectric layer 20 is shown, and the existence of this Schottky energy barrier will cause the ferroelectric capacitor to operate at low voltage. Slow down. The following is a description of the problem of the slow programming speed in low-voltage operation described above with a voltage operation and corresponding changes in the electric field in the ferroelectric dielectric layer. Figures 2 (a) to 2 (c) are graphs showing changes in the energy band and the corresponding electric field (£) in the ferroelectric dielectric layer 30 at different operating voltages, respectively. The ferroelectric dielectric layer 30 is divided into three regions of FI, F2, and F3, and the two sides of the ferroelectric dielectric layer 30 are platinum electrode layers 40 and 50. As can be seen from Figures 2 (a) to 2 (c), because the work functions of the materials of these two layers are very different, there will be band-bending phenomenon at the interface of this layer (such as 2 (a) ~ 2 (c) The figure on the left). In addition, the initial ferroelectric dielectric layer 30 performs a right-side pre-polarization (Pre-Po) under a stylized voltage (V) less than a negative coercive voltage (-Vc) (V < -Vc). 1 ar i zed) 〇 As shown in Figure 2 (a), when V = 0, its residual polarization (Remnant Polarization) comes from the two regions F2 and F3, and the F1 region is

13095twf.ptd Page 9 200527651 V. Description of the invention (3) The generated electric field is slightly reversed in the F1 area because it is in opposition to the original electric field. In addition, as shown in Figure 2 (b), when V increases to Vc, that is, at V "Vc, most of the electric fields in the F2 and F3 regions are small, and the electric field in the F2 region is approximately equal to the bridge coercive electric field (Coercive Electric Field, Ec). At this time, since the speed of area switching (Speed of Domain Switching) will decrease at a low electric field, the programming speed will decrease accordingly. Moreover, the voltage and current density The relationship diagram shows that the maximum switching current value is obtained under the condition of coercive voltage and time of 10 ms. In other words, during low voltage operation, the programming speed of the s-memory element using a ferroelectric material as a capacitor is slow. In addition, it can be seen from Figure 2 (c) that when v > Vc, polarization switching (Switch) can be performed in the F2 and F3 regions, especially the switching time in the F2 region is fast, and in most cases Since the electric field in F 3 region is still smaller than ec, it is still Slow Switching. Therefore, again from the relationship diagram of the stylized voltage and current density in Fig. 3, when the stylized voltage is increased from 15 V to 4 V, , Its cut The switching current will decrease accordingly. In addition, the problem of the slow programming speed mentioned above can also be highlighted again in the following description. Figure 4 shows the programmed pulse width (seconds) of the ferroelectric capacitor. ) And the amount of polarization, which shows the stylized voltage is -5V, # stylized voltage is _3V, ▲ stylized voltage is -2V, and the negative sign (-) indicates negative driving. As can be seen from Figure 4 As the stylized voltage decreases (eg, the operating voltage is _2V),

13095twf.ptd Page 10 200527651 V. Description of the invention (4) Polarization Loss will be particularly serious at the punch width (for example: 10 -6 seconds), that is, at high frequencies. Therefore, the problem of the slow programming speed mentioned above is related to the programming pulse width and the programming voltage. However, memory elements with fast programming speed, low operating voltage, and low power consumption are bound to become mainstream in the future market. Therefore, the problem of slow programming speed in low voltage operation is an important issue that needs to be resolved. Topic. SUMMARY OF THE INVENTION In view of this, the object of the present invention is to provide a ferroelectric capacitor to reduce or even eliminate the Schottky energy barrier between the electrode layer and the ferroelectric dielectric layer in the ferroelectric capacitor. The purpose of the present invention is to provide another ferroelectric capacitor to reduce or even eliminate the Schottky barrier between the electrode layer and the ferroelectric dielectric layer in the ferroelectric capacitor. The object of the present invention is to provide a ferroelectric device to solve the problem that the programming speed of the ferroelectric capacitor is slow under low voltage operation and a small programmed pulse width. The object of the present invention is to provide another ferroelectric device to solve the problem of slow programming speed of the ferroelectric capacitor under low voltage operation and small programming pulse width. The object of the present invention is to provide another ferroelectric element to reduce or even eliminate the Schottky energy barrier between the electrode layer and the ferroelectric dielectric layer in the ferroelectric element. The object of the present invention is to provide another ferroelectric element to reduce or even eliminate the Schottky energy barrier between the electrode layer and the ferroelectric dielectric layer in the ferroelectric element.

13095twf.ptd Page 11 200527651 V. Description of the invention (5) The present invention proposes an iron lightning electrode layer and a second electrode ^ °. This ferroelectric capacitor is composed of the ferroelectric dielectric layer between the first and the second ~ ^ F the first electrode layer and the second electrode layer the second body material ... if at least one of the first electrode layer between the one of this conductive material and the ferroelectric dielectric layer is the first electrode layer and the second; : = Pole / ferroelectric interface 'to eliminate the Schottky barrier between. s, one of them and the ferroelectric dielectric layer-electricity II Minglong: "Ferroelectric capacitors" This ferroelectric capacitor is composed of the ferroelectric dielectric layer between the first layer; two pairs of the first-electrode layer and the second electrode The material of one of the two is a conductive material, and the conductive material i:;:; === at least one of the electrode layers-with = one of the few electrode layers and the ferroelectric dielectric layer Disabled. In electric households and ferroelectric capacitors, since at least one of the first electrode layer and the ferroelectric dielectric ——and the ferroelectric dielectric layer & has:, ι,, pole / ferroelectric interface, or It is that one of the first electrode layer and the second electrode layer has a work function similar to that of the ferroelectric dielectric layer, so the first two electrode layers < at least ④ ^ 1 and the ferroelectric dielectric layer are two, Barriers are small, even without Shaw energy barriers. Therefore, under low voltage operation and stylized pulse width, the polarization loss of the ferroelectric capacitor can be reduced. The present invention proposes a ferroelectric element, which is composed of a substrate, an electric

13095twf.ptd Page 12 200527651 V. Description of the invention (6) Crystal, insulation layer, plug and ferroelectric capacitor. The transistor system is arranged on the substrate. In addition, the insulating layer is disposed on the substrate and covers the transistor. The plug is disposed in the insulating layer. In addition, the ferroelectric capacitor is disposed on the insulating layer, and the ferroelectric capacitor is electrically connected to the transistor through a plug, and the ferroelectric capacitor is configured by a first electrode layer, a second electrode layer, and A ferroelectric dielectric layer is formed between the first electrode layer and the second electrode layer. Wherein, the material of at least one of the first electrode layer and the second electrode layer is a conductive material, and the conductive material can make at least one of the first electrode layer and the second electrode layer and the ferroelectric dielectric layer There is an ohmic electrode / ferroelectric interface in between to eliminate the Schottky energy barrier between at least one of the first electrode layer and the second electrode layer and the ferroelectric dielectric layer. The invention proposes another ferroelectric element, which is composed of a substrate, a transistor, an insulating layer, a plug, and a ferroelectric capacitor. The transistor system is arranged on the substrate. In addition, the insulating layer is disposed on the substrate and covers the transistor. The plug is disposed in the insulating layer. In addition, the ferroelectric capacitor is arranged on the insulating layer, and the ferroelectric capacitor is electrically connected to the transistor through a plug, and the ferroelectric capacitor is configured by a first electrode layer, a second electrode layer, and A ferroelectric dielectric layer is formed between the first electrode layer and the second electrode layer. Wherein, the material of at least one of the first electrode layer and the second electrode layer is a conductive material, and the conductive material can make at least one of the first electrode layer and the second electrode layer have a dielectric with this ferroelectricity. The layers have similar work functions to reduce the Schottky energy barrier between at least one of P of the first electrode layer and the second electrode layer and the ferroelectric dielectric layer. In the above ferroelectric element, since the first electrode in the ferroelectric capacitor

13095twf.ptd Page 13 200527651

At least one of the first electrode layer and the second electrode layer and the ferroelectric ohmic electrode / ferroelectric interface, or at least one of the first electrode layer and the first two electrode 1 layer / has a similarity to this ferroelectric dielectric layer The work function, therefore, the Schottky energy barrier between at least one of the first electrode layer and the second electrode layer and the ferroelectric dielectric layer is small, or there is no Schottky energy barrier. Therefore, the performance of the ferroelectric device can be improved under low voltage operation and a small programmed pulse width. In particular, when a ferroelectric element is applied to a memory element, a ^ memory element having characteristics such as fast programming speed, low operating voltage, and low power consumption can be obtained. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, preferred embodiments are described below in detail with the accompanying drawings, as follows. [Embodiment] The following is a description of the ferroelectric capacitor and the ferroelectric element of the present invention by taking the ferroelectric element as an example, but it is not used to limit the application of the present invention. 〃 FIG. 5 ′ shows a schematic cross-sectional view of a ferroelectric device according to a preferred embodiment of the present invention. Referring to FIG. 5, the ferroelectric element of the present invention is composed of a substrate, a transistor 10, an insulating layer 1 12, a plug 1 16, and a ferroelectric capacitor 1 2 6. The transistor 102 is arranged on the substrate 100, and the transistor 102 is composed of a gate dielectric layer 104, a gate conductor layer 106, and a source / drain region 108. And the partition wall 1 1 〇. The gate conductor layer 106 is disposed on the substrate 100. In addition, the gate dielectric layer 104 is disposed between the substrate 100 and the gate conductor layer 106. In addition, the source / drain region 108 is disposed on both sides of the gate conductor layer 106.

13095twf.ptd Page 14 200527651 V. Description of the invention (8) 't ° In addition, the spacer UG is arranged on the side wall of the gate conductor layer 106. In addition, the insulating layer U2 in the ferroelectric element is disposed on the substrate 100 and covers the transistor 102. The material of the insulating layer 112 is, for example, silicon oxide, silicon nitride, silicon oxynitride, or other suitable materials. In addition, the plug 1 1 6 is disposed in the insulating layer 2 and the material of the plug 6 is, for example, aluminum, tungsten, or other suitable conductive materials. In addition, the ferroelectric capacitor 126 is disposed on the insulating layer 112, and the ferroelectric capacitor 126 is electrically connected to the source / drain region 108 of the transistor 1 16 through the plug 116. The ferroelectric capacitor 126 is composed of electrode layers 120 and 124 and a ferroelectric dielectric layer 122 disposed between the electrode layers 120 and 124. Among them, the first substance of iron ^ is, for example, lead osmium titanate, lead lanthanum titanate, gallium bismuth acid, ^ tantalum bismuth acid, barium acid, barium osmium acid, or other suitable materials, & at In a preferred embodiment, the material of the capacitors in the ferroelectric capacitor 126 is, for example, platinum (Pt), and the material of the electrode layer 124 is, for example, ΪίΠ, and the conductor material includes a conductor oxide, which is, for example, Lanthanum nickel, LN0), hafnium oxide (RU〇2), silver oxide (IrO2), steel in: = oxide (Lai_xSrxCo03) or other suitable conductor materials. The use of a two-material gate as the electrode layer 124 ′ can make the electrode layer 124 and iron 6A ^, 74 have an ohmic electrode / ferroelectric interface, that is, the two-layer-based energy barrier. Or, in another preferred embodiment, the electrode layer 124 has a work function similar to that of the ferroelectric dielectric layer 122; ii, the Schottky barrier between the 12f / 124 and the ferroelectric dielectric layer 122, ' The difference in work function between the middle electrode layer 124 and the ferroelectric dielectric layer 122 is between

200527651 V. Description of the invention (9) Between 0 and 0.5eV. In this way, compared with the conventional two-effect t electric power, it is possible to perform complicated operations and f under the small stylized pulse width. In particular, the ferroelectric element is applied to the memory element; the speed is changed; and it can be operated at a lower voltage. Of course, in another preferred embodiment, if the material of the electrode layer 120 is the above-mentioned bean The material of 1 24 in the middle device 126 is, for example, platinum, mesh, and Φ + f conductor material is shaken, and the function of the electrode layer is also the same as the above-mentioned + μ Ϊ f ί, in another more In the preferred embodiment, if the ferroelectric capacitor 1 26 2 has little or no energy barrier at the interface of the film layer, the performance of the ferroelectric capacitor 126 will be better than that of the above-mentioned two-fan king / yes' and can be lower. Operation under voltage: The purpose of reducing power consumption. As it happens, the material of the electrode layer 120 in the ferroelectric capacitor 126 is platinum, the layer 2 of it is lanthanum nickel oxide (LaNi〇3, LN〇), and the material of the iron-specific electrical layer 122 is iron. For the case of erbium titanate (ρζτ) as an example, it is illustrated that the present invention's evening hybrids 6ia) to 6 (C) respectively show the energy bands in the 22 electric layer 122 and the corresponding ones under different operating voltages. In the electric field change diagram, Huangru fD electric " electric layer 122 is divided into three regions of F1, F2, and F3, and the left side of the bean is the Pt electrode layer 120 and the right side is the LN0 electrode layer 124. Eight 200527651

As can be seen from Figs. 6 (a) to 6 (c), since there is still a Schottky barrier between the electrode layer 120 and the ferroelectric dielectric layer 122, there is still a phenomenon that the band is bent there. However, since the electrode layer 124 and the ferroelectric dielectric layer 122 have the same work function, it is known that the phenomenon that the energy band bending originally existing there disappears, so that the power loss there can be reduced, and the amount of polarization can be solved. Attrition. In addition, FIG. 7 is a graph showing the relationship between the stylized pulse width and the normalized polarization of the green ferroelectric capacitor. Among them, represents the capacitance

It is an asymmetric Pt electrode layer / PZT ferroelectric dielectric layer / LN0 electrode layer capacitor '⑩ means that the capacitor is symmetrical and the electrode layer / ρζτ ferroelectric dielectric layer / Pt electrode layer capacitor, and the upper half of the The "solid line" part indicates the result obtained by the positive driving, and the "dotted line r in the lower half" indicates the result obtained by the negative driving. It can be seen from FIG. 7 that when the L N 0 electrode layer is driven in a forward direction, the polarization reversal (CPolarization Reversal) has nothing to do with the programmed pulse width. This is because the interface between the PZT ferroelectric dielectric layer and the L N0 electrode layer is an ohmic electrode / ferroelectric interface, that is, they have the same work function without Schottky energy barriers (as shown in Figures 6 (a) ~ 6 (c)). ) Exists, so you can eliminate the factors that cause slow switching here. However, if it is driven in the negative direction, that is, when the voltage is negatively biased, the LN0 electrode layer will not be subjected to any impact, that is, the problem of loss of polarization will still exist. This is because there is still a Xiaoji barrier between the Pt electrode layer and the ρζτ ferroelectric dielectric layer (as shown in Fig. 6 (a) ~ 6 (c)), so in the F 3 region < Art still has the problem of slow switching. Therefore, the ohmic electrode / ferroelectric interface (or the work function between the two layers) is selected at the bottom of the ferroelectric dielectric layer.

I

13095twf.ptd Page 17 200527651 V. Description of the invention (π) The electrode layer has a small difference, which can effectively improve the programming speed of the ferroelectric capacitor, and it can also operate at low voltage. In summary, the present invention has at least the following advantages: 1. In the ferroelectric capacitor of the present invention, since at least one of the electrode layer 120 and the electrode layer 124 has an ohmic electrode between the ferroelectric dielectric layer 122 / Ferroelectric interface, or at least one of the electrode layer 120 and the electrode layer 124 has a work function similar to that of the ferroelectric dielectric layer 122. Therefore, at least one of the electrode layer 120 and the electrode layer 124 and the ferroelectric The Schottky energy barrier between the electrical layers 122 is relatively small, even without the Schottky energy barrier. Thus, under low voltage operation and a small stylized pulse width, the polarization loss of the ferroelectric capacitor 126 can be reduced. 2. In the above-mentioned ferroelectric elements, especially in the application of memory elements', because the Schottky energy barrier of the electrode layer and the ferroelectric dielectric layer in the ferroelectric capacitor is small, there is no Schottky energy barrier. Therefore, a memory element with fast programming speed, low operating voltage, and low power consumption can be obtained. 3. The ferroelectric stack structure of the present invention can also be applied to other components to form other types of ferroelectric components. For example, a ferroelectric stacked junction having the electrode layer 120, the ferroelectric dielectric layer 122, and the electrode layer 124 of the present invention can be used in a non-volatile memory element such as a ferroelectric memory to improve performance. Although the present invention has been disclosed in the preferred embodiment as above, it does not limit the present invention. 'Any person skilled in the art can make some changes and decorations without departing from the scope of the present invention: Invention :: The scope shall be determined by the scope of the attached patent application. "" Man

13〇twf.ptd Page 18 200527651 Brief Description of Drawings Figure 1 is an energy level diagram obtained by combining an electrode layer and a ferroelectric dielectric layer in a conventional ferroelectric capacitor. Figures 2 (a) to 2 (c) are the changes in the energy band and corresponding electric field (E) of the obtained ferroelectric dielectric layer under different operating voltages in conventional ferroelectric capacitors. Figure 3 is a graph showing the relationship between the programmed voltage and current density of a conventional ferroelectric capacitor. Fig. 4 is a graph showing the relationship between the stylized pulse width and the amount of polarization of a conventional ferroelectric capacitor. Fig. 5 is a schematic sectional view of a ferroelectric device according to a preferred embodiment of the present invention. < · Figures 6 (a) ~ 6 (c) are the changes in the energy band and corresponding electric field (E) of the obtained ferroelectric dielectric layer under different operating voltages in the ferroelectric capacitor of the present invention. Illustration. Fig. 7 is a graph showing the relationship between the stylized pulse width and the normalized polarization amount of ferroelectric capacitors according to the present invention and the conventional ferroelectric capacitors. [Explanation of drawing symbols] 10, 40, 50, 120, 124 ·· Electrode layer 20, 30, 122: Ferroelectric dielectric layer 100: Substrate 1 0 2: Transistor 1 04: Gate dielectric layer · 1 0 6: Gate conductor layer 10 8 Source and electrode area

13095twf.ptd Page 19 200527651

13095twf.ptd Page 20

Claims (1)

200527651 VI. Scope of patent application 1. Two types: Ferroelectric capacitors, a first electrode layer; dagger · a second electrode layer; and a ferroelectric dielectric layer, disposed between the first, 4 θ A β second electrode layer, wherein the material of the first electrode layer and the second electrode is a conductor material, and the conductor material is two of one layer and at least one of the second electrode layer and the first electrode layer. An electrode has an Ohmic electrode / ferroelectric interface, and the first electrode layer and the Schottky Barrier are interposed between at least one of the second electrode layers between the electrical layers. Xiao Jidao between the two layers of electric power is the ferroelectric capacitor described in item 1 of the declared patent scope, wherein the conductor material includes a conductive oxide. 1 The ferroelectric capacitor described in item 2 of the patent application scope, The conductor oxide includes lanthanum nickel oxide (LaNi〇3, ln〇), rhodium oxide (Ru02), iridium oxide (IrO2), and lanthanum gill cobalt oxide (Lai x Srx Co. 03). The ferroelectric capacitor according to item 1 of the scope of the patent application, wherein the material of the dielectric layer 1 includes lead titanate zirconate, lead titanate lanthanum zirconate, niobium acid recorder, strontium niobate, barium titanate, and titanium One of lithium barium acid. 5. The ferroelectric capacitor according to item 1 of the scope of the patent application, wherein the material of one of the first electrode layer and the second electrode layer is the conductive material, and the other material includes platinum (Pt). 6 · —Ferroelectric capacitors, including: Page 21 13095twf.ptd 200527651 6. Patent application scope-a first electrode layer; a second electrode layer; and a ferroelectric dielectric layer disposed between the first electrode layer and the second electrode layer, wherein the The material of at least one of the first electrode layer and the second electrode layer is a conductive material, and the conductive material can make at least one of the first electrode layer and the second electrode layer have the same properties as the ferroelectricity. The dielectric layer has a similar work function to reduce the Schottky energy barrier between at least one of the first electrode layer and the second electrode layer and the ferroelectric dielectric layer. 7. The ferroelectric capacitor according to item 6 of the scope of patent application, wherein a difference in a work function between at least one of the first electrode layer and the second electrode layer and the ferroelectric dielectric layer is between Between 0 and 0.5 e V. 8. The ferroelectric capacitor according to item 6 of the patent application scope, wherein the conductive material includes a conductive oxide. 9. The ferroelectric capacitor according to item 8 in the scope of the patent application, wherein the conductive oxide includes lanthanum nickel oxide (LaNi03, LN0), rhodium oxide (Ru02), iridium oxide (Ir02), and lanthanum samarium cobalt oxide ( LahSrxCoOs) Among them, the ferroelectric capacitor as described in item 6 of the scope of the patent application, wherein the material of the ferroelectric dielectric layer includes titanium oxide, acid oxide, steel error, group wire acid record, and sharp group wire. One of acid recording, barium titanate and barium titanate recording. 11. The ferroelectric capacitor according to item 6 of the scope of patent application, wherein the material of one of the first electrode layer and the second electrode layer is the conductor material, and the other material includes platinum. 13095twf.ptd Page 22 200527651 Sixth, the scope of patent application 1 2 · a kind of ferroelectric element a substrate; a transistor disposed on the substrate; an insulating layer disposed on the substrate, and a plug, which is placed in the reading insulating layer; The transistor is held by J; a ferroelectric capacitor is disposed on the insulating lug and is electrically connected to the transistor through the plug; 4 the ferroelectric ferroelectric capacitor has a first electrode layer; the electric capacitor includes: a second An electrode layer; and a ferroelectric dielectric layer disposed between the electrode layers. The material of the first electrode layer and the second electrode is the conductor layer and at least one of the electrode layers and The second to f-body materials of the second electrode layer can make at least one of the first and second electrode layers and the barrier of the first ^ ^ ^ ^ t ^ t ^ ^ ^ ^ ^ ^ Xiao Jieneng between the ferroelectric dielectric layer and the ferroelectric dielectric layer. As described in the patent application, the conductor material includes a conductor oxide. The ferroelectric element covered by the item 'wherein the conductor V is almost the same as the ferroelectric element described in item 13 of the fW section of the v statement', wherein the substance includes lanthanum nickel oxide (LaNi03, LN0), rhodium oxide (ru02 _ 15. Of the iridium oxide (IrO2) and lanthanum gill cobalt oxide (Lai xSrxCOO3) 15. The ferroelectric device according to item 12 of the patent application scope, wherein Page 23 200527651 VI. Patent Application Materials of ferroelectric dielectric layers include lead titanium zirconate, lead lanthanum zirconate titanate, hafnium tantalum bismuth acid, lithium niobium tantalum bismuthate, barium titanate and lithium barium titanate. One. 1 6. The ferroelectric device according to item 12 of the scope of patent application, wherein the material of one of the first electrode layer and the second electrode layer is a conductive material, and the other material includes platinum. 1 7. A ferroelectric element comprising: a substrate; a transistor disposed on the substrate; an insulating layer disposed on the substrate and covering the transistor; a plug disposed on the insulating layer And a ferroelectric capacitor disposed on the insulating layer, and the ferroelectric capacitor is electrically connected to the transistor through the plug, the ferroelectric capacitor includes: a first electrode layer; a second electrode layer And a ferroelectric dielectric layer disposed between the first electrode layer and the second electrode layer, wherein a material of at least one of the first electrode layer and the second electrode layer is a conductive material, And the conductor material can make at least one of the first electrode layer and the second electrode layer have a work function similar to that of the ferroelectric dielectric layer, so as to reduce at least one of the first electrode layer and the second electrode layer. The Schottky barrier between one of them and the ferroelectric dielectric layer. 18. The ferroelectric device according to item 17 of the scope of patent application, wherein a difference in a work function between at least one of the first electrode layer and the second electrode layer and the ferroelectric dielectric layer is between Between 0 and 0.5 e V. 13095twf.ptd Page 24 200527651 VI. Scope of Patent Application 19 • The ferroelectric device described in item 17 of the scope of patent application, wherein the conductor material includes a conductor oxide. 2 0. The ferroelectric device according to item 19 of the scope of patent application, wherein the conductive oxide includes lanthanum nickel oxide (LaNi03, LN0), rhodium oxide (Ru02), iridium oxide (Ir02), and lanthanum-cobalt oxide The ferroelectric device described in item 17 of the scope of patent application, wherein the material of the ferroelectric dielectric layer includes lead zirconate titanate, lead lanthanum titanate titanate, tantalum bismuth One of rhenium acid, osmium niobium tantalum bismuth acid, barium titanate and barium osmium titanate. 2 2. The ferroelectric device according to item 17 of the scope of patent application, wherein the material of one of the first electrode layer and the second electrode layer is a conductive material, and the material of the other includes platinum. 13095twf.ptd Page 25