阅读说明：本技术 一种铁电电容和铁电场效应晶体管及制备方法 (Ferroelectric capacitor, ferroelectric field effect transistor and preparation method ) 是由 韩根全 彭悦 刘艳 郝跃 于 2020-04-23 设计创作，主要内容包括：本发明公开了一种铁电电容,所述薄膜铁电电容包括顺序叠置的衬底、介质层和上电极,所述介质层包括至少一层不定型氧化物薄膜或者多晶氧化物薄膜。本发明所述铁电电容的介质层采用不定型氧化物薄膜或者多晶氧化物薄膜,不再局限于单晶或者多晶的铁电材料,即使是非晶氧化物薄膜材料也可以实现铁电特性。本发明还公开了所述铁电电容的制备方法。本发明还公开了一种铁电场效应晶体管,本发明所述铁电场效应晶体管栅介质层包括至少一层不定型氧化物薄膜或者多晶氧化物薄膜,使得铁电场效应晶体管的栅介质厚度可以降低至2nm以下,且能保持稳定的铁电场效应晶体管特性,同时极大的降低了栅泄漏电流。本发明还公开了铁电场效应晶体管的制备方法。(The invention discloses a ferroelectric capacitor, which comprises a substrate, a dielectric layer and an upper electrode which are sequentially stacked, wherein the dielectric layer comprises at least one layer of amorphous oxide film or polycrystalline oxide film. The dielectric layer of the ferroelectric capacitor adopts an amorphous oxide film or a polycrystalline oxide film, is not limited to a single crystal or polycrystalline ferroelectric material any more, and can realize ferroelectric characteristics even if the dielectric layer is an amorphous oxide film material. The invention also discloses a preparation method of the ferroelectric capacitor. The invention also discloses a ferroelectric field effect transistor, and the gate dielectric layer of the ferroelectric field effect transistor comprises at least one layer of amorphous oxide film or polycrystalline oxide film, so that the thickness of the gate dielectric of the ferroelectric field effect transistor can be reduced to below 2nm, the stable characteristics of the ferroelectric field effect transistor can be maintained, and the gate leakage current is greatly reduced. The invention also discloses a preparation method of the ferroelectric field effect transistor.)

1. A ferroelectric capacitor, characterized in that the thin film ferroelectric capacitor comprises a substrate, a dielectric layer and an upper electrode which are sequentially stacked, wherein the dielectric layer comprises at least one amorphous oxide film or polycrystalline oxide film.

2. The ferroelectric capacitor according to claim 1, wherein the amorphous oxide thin film or the polycrystalline oxide thin film is Al₂O₃、HfO₂、ZrO₂、SiO₂、TiO₂、La₂O₃And Y₂O₃At least one of (1).

3. The ferroelectric capacitor of claim 1, wherein the substrate is a semiconductor material or a metal material.

4. A method for manufacturing a ferroelectric capacitor as in any one of claims 1 to 3, comprising the steps of: and forming a dielectric layer on the substrate, and then forming an upper electrode layer on the dielectric layer to obtain the ferroelectric capacitor.

5. A ferroelectric field effect transistor is characterized in that the ferroelectric field effect transistor comprises a substrate, a source electrode region and a drain electrode region, wherein the source electrode region and the drain electrode region are arranged on the substrate in an isolated mode through a channel; the gate dielectric layer comprises at least one amorphous oxide film or polycrystalline oxide film.

6. The ferroelectric field effect transistor as claimed in claim 5, wherein said amorphous oxide thin film or polycrystalline oxide thin film is Al₂O₃、HfO₂、ZrO₂、SiO₂、TiO₂、La₂O₃And Y₂O₃At least one of (1).

7. A ferroelectric field effect transistor as in claim 5, wherein said substrate is a semiconductor.

8. A ferroelectric field effect transistor according to claim 5, wherein the thickness of the source and drain electrodes is 20 to 30 nm.

9. A method for manufacturing a ferroelectric field effect transistor as defined in any one of claims 5 to 8, comprising the steps of:

(1) forming a gate dielectric layer on a substrate;

(2) forming a gate electrode on the gate dielectric layer;

(3) selecting a source region, a gate region and a drain region on the gate electrode, and etching the source region and the drain region on two sides of the gate region;

(4) subjecting the substrate on both sides of the gate region to an energy in the range of 20-30KeV and a dose in the range of 1E10¹⁵-2E10¹⁵cm^-3Forming doped source and drain regions, wherein the substrate region between the source and drain regions which is not implanted with ions is the channel;

(5) and depositing metal above the source region and the drain region to form a source electrode and a drain electrode to obtain the ferroelectric field effect transistor.

10. A method of manufacturing a ferroelectric field effect transistor as set forth in claim 9, characterized in that at least one of the following (a) to (d) is:

(a) in the step (1), the forming of the gate dielectric layer on the substrate is as follows: depositing a gate dielectric layer on the substrate by utilizing atomic layer deposition, magnetron sputtering or pulsed laser deposition;

(b) in the step (2), a gate electrode is formed on the gate dielectric layer: depositing metal on the gate dielectric layer by utilizing a magnetron sputtering process to form a gate electrode;

(c) in the step (3), the source region, the gate region and the drain region selected on the gate electrode are selected on the gate electrode by using a photolithography process;

(d) in the step (5), the deposition is electron beam deposition.

Technical Field

The invention belongs to the technical field of microelectronic devices, and particularly relates to an oxide film ferroelectric capacitor and a ferroelectric field effect transistor based on oxygen vacancy charge regulation and control and a preparation method thereof.

Background

The electronic information industry plays an extremely important role in expanding social employment, promoting economic growth, enhancing international competitiveness and maintaining national safety, and new materials, new structures and new processes required by the development of the electronic information industry are always listed as key development objects by all semiconductor strong countries. The ferroelectric field effect transistor has the advantages of fast read-write response, high current driving capability, low power consumption, nondestructive reading and the like, and is an indispensable class in modern logic devices and memory devices.

The ferroelectric field effect transistor adopts a polycrystalline or single crystal ferroelectric film as a gate dielectric layer, and utilizes the polarization charge of the ferroelectric film to modulate the channel conductance of the transistor, thereby controlling the switching characteristic and the storage characteristic of the transistor. In recent research, most of the conventional perovskite ferroelectric materials and doped hafnium oxide ferroelectric thin films are adopted, and then the conventional ferroelectric field effect transistors made of the conventional perovskite ferroelectric materials have the following defects:

(1) the ferroelectric field effect transistor using the ferroelectric film with the traditional perovskite structure as the gate dielectric is incompatible with the existing integrated process platform. On the one hand, the ferroelectric thin film material with the traditional perovskite structure contains high chemical activity heavy metal ions, and the heavy metal ions are a fatal pollution source causing the failure of an integrated circuit. On the other hand, the preparation temperature of the traditional ferroelectric film is higher, which increases the cross contamination between the ferroelectric film and the silicon integrated circuit while improving the process difficulty. The cross-contamination problem is mainly solved by establishing a special production line for the ferroelectric field effect transistor and adding a process protection element substrate. This approach not only increases the threshold for the development of ferroelectric field effect transistors, but also increases the manufacturing cost of the chip.

(2) Although the film material can be obtained by utilizing the atomic layer deposition technology in the ferroelectric field effect transistor adopting the doped hafnium oxide ferroelectric film as the gate dielectric, a serious interface state exists between the film material and the substrate, so that high leakage current is generated in a device, the performance of the ferroelectric field effect transistor is influenced, the ferroelectric property of the ferroelectric field effect transistor can be realized only after the ferroelectric field effect transistor is crystallized by an annealing process with the temperature higher than 650 ℃, and the process can not be compatible with the existing CMOS gate-last process.

(3) Due to the influence of the size effect, the ferroelectricity of the conventional ferroelectric thin film suddenly decreases with the decrease of the thickness of the ferroelectric thin film, and particularly when the thickness is less than 10nm, the ferroelectricity disappears, so that the requirement of the existing chip design with high integration level cannot be met. While the existing hafnium oxide doped ferroelectric thin film can still produce ferroelectric properties at a thickness of less than 10nm, the reduction of the thin film thickness is still limited due to the polycrystalline structure, and from the current reports, the thin film thickness is generally greater than 5nm, and for the advanced node FinFET or stacked nanosheet FET, the ferroelectric layer thickness still needs to be further reduced.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides an oxide film ferroelectric capacitor and a ferroelectric field effect transistor based on oxygen vacancy charge regulation and preparation methods thereof.

In order to achieve the purpose, the invention adopts the technical scheme that: a thin film ferroelectric capacitor comprises a substrate, a dielectric layer and an upper electrode which are sequentially stacked, wherein the dielectric layer comprises at least one amorphous oxide thin film or polycrystalline oxide thin film.

The dielectric layer of the ferroelectric capacitor adopts the amorphous oxide film or the polycrystalline oxide film, is not limited to the single-crystal ferroelectric material any more, can realize the ferroelectric property even if the amorphous oxide film or the polycrystalline amorphous oxide film is adopted, and can effectively reduce the thickness of the gate dielectric of the ferroelectric film under the condition of ensuring the leakage current. The dielectric layer may be formed entirely of an amorphous oxide thin film, entirely of a polycrystalline oxide thin film, or partially of an amorphous oxide and partially of a polycrystalline oxide thin film, and preferably, the gate dielectric layer is an amorphous oxide thin film.

As a preferred embodiment of the ferroelectric capacitor of the present invention, the amorphous oxide thin film or the polycrystalline oxide thin film is Al₂O₃、HfO₂、ZrO₂、SiO₂、TiO₂、La₂O₃And Y₂O₃At least one of (1).

As a preferred embodiment of the ferroelectric capacitor according to the present invention, the substrate is a semiconductor material or a metal material.

The invention also aims to provide a preparation method of the ferroelectric capacitor, which comprises the following steps: and forming a dielectric layer on the substrate, and then forming an upper electrode layer on the dielectric layer to obtain the ferroelectric capacitor.

As a preferred embodiment of the method for manufacturing a ferroelectric capacitor according to the present invention, the forming a dielectric layer on a substrate is: and depositing a dielectric layer on the substrate by adopting atomic layer deposition, magnetron sputtering or pulsed laser deposition.

As a preferred embodiment of the method for manufacturing a ferroelectric capacitor according to the present invention, the forming of the upper electrode layer on the dielectric layer is: and depositing metal on the dielectric layer by utilizing a magnetron sputtering or atomic layer deposition process, and forming an upper electrode by utilizing photoetching, or forming the upper electrode on the dielectric layer by utilizing a photoetching stripping process.

The invention also aims to provide a ferroelectric field effect transistor, which comprises a substrate, a source region and a drain region, wherein the source region and the drain region are arranged on the substrate in an isolated mode through a channel; the gate dielectric layer comprises at least one amorphous oxide film or polycrystalline oxide film.

The principle of the ferroelectric characteristics of the ferroelectric field effect transistor and the ferroelectric capacitor in the present invention can be illustrated by fig. 1. After voltage is applied, oxygen vacancies and oxygen ions are formed at the interface, and an electric dipole generating a polarization effect is obtained by separating the oxygen vacancies and the oxygen ions, and the polarization process can be changed under the action of different voltages. The oxygen vacancy charge regulation mechanism is utilized to enable the amorphous oxide film to generate ferroelectricity, and the generated ferroelectricity can be applied to storage switchable devices.

The ferroelectric gate dielectric layer of the ferroelectric field effect transistor of the present invention is no longer limited to single crystal or polycrystalline ferroelectric materials, the amorphous oxide thin film material can realize ferroelectric property, further reduce the thickness of the gate dielectric of the ferroelectric field effect transistor to below 2nm, since the polycrystalline or single crystal oxide thin film material is used, when the material is thin to a certain extent, for example, below 2nm, the leakage current leaks along the grain boundary of the single crystal or polycrystalline crystal grains, causing a sharp increase in leakage current, the amorphous oxide film has no crystal boundary, the thickness is reduced to below 2nm, the stable ferroelectric field effect transistor characteristic can be still maintained, meanwhile, the gate leakage current is greatly reduced, the conduction current of the transistor is improved, further improving the performance of the device, the operation speed of the ferroelectric field effect transistor can reach more than 100 ns.

The gate dielectric layer may be formed of an amorphous oxide film, a polycrystalline oxide film, a partially amorphous oxide film and a partially polycrystalline oxide film, and is preferably an amorphous oxide film.

As a preferred embodiment of the ferroelectric field effect transistor of the present invention, the amorphous oxide thin film or the polycrystalline oxide thin film is Al₂O₃、HfO₂、ZrO₂、SiO₂、TiO₂、La₂O₃And Y₂O₃At least one of (1). The gate electrode may be selected from materials commonly used for gate electrodes, such as metal materials.

As a preferred embodiment of the ferroelectric field effect transistor of the present invention, the substrate is a semiconductor.

In a preferred embodiment of the ferroelectric field effect transistor according to the present invention, the source electrode and the drain electrode have a thickness of 20 to 30 nm.

The invention also aims to provide a preparation method of the ferroelectric field effect transistor, which comprises the following steps:

(1) forming a gate dielectric layer on a substrate;

(2) forming a gate electrode on the gate dielectric layer;

(3) selecting a source region, a gate region and a drain region on the gate electrode, and etching the source region and the drain region on two sides of the gate region;

(4) subjecting the substrate on both sides of the gate region to an energy in the range of 20-30KeV and a dose in the range of 1E10¹⁵-2E10¹⁵cm^-3Forming doped source and drain regions, wherein the substrate region between the source and drain regions which is not implanted with ions is the channel;

(5) and depositing metal above the source region and the drain region to form a source electrode and a drain electrode to obtain the ferroelectric field effect transistor.

As a preferred embodiment of the method for manufacturing a ferroelectric field effect transistor according to the present invention, in step (1), the forming a gate dielectric layer on a substrate is: and depositing a gate dielectric layer on the substrate by utilizing atomic layer deposition, magnetron sputtering or pulsed laser deposition.

As a preferred embodiment of the method for manufacturing a ferroelectric field effect transistor according to the present invention, in step (2), the gate electrode is formed on the gate dielectric layer by: and depositing metal on the gate dielectric layer by utilizing a magnetron sputtering process to form a gate electrode.

As a preferred embodiment of the method for manufacturing a ferroelectric field effect transistor according to the present invention, in the step (3), the selecting of the source region, the gate region, and the drain region on the gate electrode is selecting the source region, the gate region, and the drain region on the gate electrode by using a photolithography process.

As a preferred embodiment of the method for manufacturing a ferroelectric field effect transistor according to the present invention, in the step (5), the deposition is electron beam deposition.

The invention has the beneficial effects that: the invention provides a ferroelectric capacitor, wherein a dielectric layer of the ferroelectric capacitor adopts an amorphous oxide film or a polycrystalline oxide film, is not limited to a single crystal or polycrystalline ferroelectric material any more, and can realize ferroelectric characteristics even if the dielectric layer is an amorphous oxide film material. The invention also provides a preparation method of the ferroelectric capacitor. The invention also provides a ferroelectric field effect transistor, the ferroelectric gate dielectric layer of the ferroelectric field effect transistor is not limited to single crystal or polycrystalline ferroelectric materials any more, and the ferroelectric property can be realized even if the ferroelectric gate dielectric layer is an amorphous oxide film material, so that the thickness of the gate dielectric of the ferroelectric field effect transistor can be further reduced to be less than 2nm, the stable ferroelectric field effect transistor property can be maintained, meanwhile, the gate leakage current is greatly reduced, the conduction current of the transistor is improved, and the device performance is further improved. The invention also provides a preparation method of the ferroelectric field effect transistor, the ferroelectric field effect transistor is compatible with the existing mainstream integrated circuit process, and the cross contamination between the ferroelectric film and the silicon integrated circuit is avoided on the premise of not establishing a special production line for the ferroelectric field effect transistor and increasing working procedures.

Drawings

FIG. 1 is a schematic diagram of the ferroelectric characteristics of a ferroelectric field effect transistor and a ferroelectric capacitor according to the present invention;

FIG. 2 is a schematic structural diagram of a ferroelectric capacitor according to an embodiment of the present invention; wherein, (1) an upper electrode; (2) a dielectric layer; (3) a substrate;

FIG. 3 is a schematic structural diagram of a ferroelectric field effect transistor according to an embodiment of the present invention; wherein, (4) a substrate; (5) a channel; (6) a source region; (7) a drain region; (8) a gate dielectric layer; (9) a source electrode; (10) a drain electrode; (11) a gate electrode;

FIG. 4 is a schematic diagram illustrating a manufacturing process of a ferroelectric capacitor according to an embodiment of the present invention;

FIG. 5 shows the results of testing the ferroelectric characteristics of the ferroelectric capacitor according to example 1;

FIG. 6 shows the reliability test results of the ferroelectric characteristics of the ferroelectric capacitor according to example 1;

FIG. 7 is a schematic diagram of a process for fabricating a ferroelectric field effect transistor according to an embodiment of the present invention;

FIG. 8 is a high resolution transmission electron micrograph of aluminum oxide and zirconium oxide films prepared on germanium substrates from examples 2 and 3.

Detailed Description

To better illustrate the objects, aspects and advantages of the present invention, the present invention will be further described with reference to specific examples.

A schematic structural diagram of the ferroelectric capacitor according to an embodiment of the present invention is shown in fig. 2, where the thin film ferroelectric capacitor includes a substrate (3), a dielectric layer (2) and an upper electrode (1) stacked in sequence, and the dielectric layer includes at least one amorphous oxide film or polycrystalline oxide film; the substrate 1 is made of a semiconductor material or a metal material.

A schematic structural diagram of the ferroelectric field effect transistor according to an embodiment of the present invention is shown in fig. 3, where the ferroelectric field effect transistor includes a substrate (4), and a source region (6) and a drain region (7) which are provided on the substrate (4), the source region (6) and the drain region (7) are isolated by a channel (5), a gate dielectric layer (8) is provided on the source region (6), the drain region (7) and the channel (5), a source electrode (9) is provided on the source region (6), a drain electrode (10) is provided on the drain region (7), and a gate electrode (11) is provided on the gate dielectric layer (8); the gate dielectric layer (8) comprises at least one amorphous oxide film or polycrystalline oxide film.