CN110970554B - Barium titanate single crystal epitaxial film threshold switch device and preparation method thereof - Google Patents
Barium titanate single crystal epitaxial film threshold switch device and preparation method thereof Download PDFInfo
- Publication number
- CN110970554B CN110970554B CN201911257017.4A CN201911257017A CN110970554B CN 110970554 B CN110970554 B CN 110970554B CN 201911257017 A CN201911257017 A CN 201911257017A CN 110970554 B CN110970554 B CN 110970554B
- Authority
- CN
- China
- Prior art keywords
- barium titanate
- film
- substrate
- single crystal
- nsto
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N50/00—Galvanomagnetic devices
- H10N50/10—Magnetoresistive devices
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N50/00—Galvanomagnetic devices
- H10N50/01—Manufacture or treatment
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N50/00—Galvanomagnetic devices
- H10N50/80—Constructional details
- H10N50/85—Magnetic active materials
Abstract
The application discloses a barium titanate single crystal epitaxial thin film threshold switch device and a preparation method thereof, which belong to the technical field of physical chemical synthesis and electronic information, and the preparation method comprises the following steps: (1) taking NSTO as a substrate, putting the cleaned NSTO substrate into a pulse laser deposition system, taking barium titanate ceramic as a target material, growing a barium titanate film, carrying out in-situ annealing after the growth is finished, cooling to room temperature under the protection of oxygen atmosphere, and taking out a sample; (2) covering a mask plate on the surface of the barium titanate film, and evaporating a chromium film; (3) then performing thermal evaporation on the chromium film to form a metal Au film; (4) and pressing metal indium wires or indium grains on the back of the substrate to be used as a lower electrode to obtain the single crystal epitaxial barium titanate film threshold switch device, wherein the structure of the device is Au/Cr/BTO/NSTO/In.
Description
Technical Field
The invention relates to the technical field of physical and chemical synthesis and electronic information, in particular to a barium titanate single crystal epitaxial film threshold switch device and a preparation method thereof.
Background
Many oxide materials have bistable resistance states, switching speeds up to nano-second order, and power consumption down to microwatts, and thus can be used for nonvolatile Resistive Random Access Memories (RRAMs). However, RRAM devices suffer from potential current paths caused by leakage currents, limiting their development. The threshold resistance change device is connected with the RRAM in series, so that leakage current can be reduced, and the potential current channel problem is solved. Therefore, the threshold resistance change device is critical to realize RRAM memory applications. In addition, the threshold resistance change effect can also be used for synaptic devices of neural network calculation.
Barium titanate BaTiO3(BTO) has been discovered by American and Su scholars as a well-known ferroelectric and piezoelectric material as early as 1942. In addition to the ferroelectric effect, the barium titanate thin film has bipolar and unipolar resistance change characteristics. SrTiO of the existing Nb-doped strontium titanate3The memristor with (NSTO) as the substrate is mostly in a conventional metal (Pt, Au)/BTO/NSTO/structure and has a stable bipolar or unipolar resistance change phenomenon. Recently, BaTiO has been reported3The amorphous film has a threshold resistance change effect. The invention is tested and researched in vacuum condition in BaTiO3A layer of metal chromium and gold thin film electrode is evaporated on the/NSTO epitaxial heterojunction, metal indium is used as a lower electrode, new electrical characteristics are obtained by changing the structure of the device, and the threshold switch device with the Au/Cr/BTO/NSTO/In structure is prepared; the change from the conventional metal (Pt, Au)/BTO/NSTO/In to Au/Cr/BTO/NSTO/In changes the resistance change characteristic, and obtains stable threshold switch characteristic.
Disclosure of Invention
The invention aims to provide a barium titanate single crystal epitaxial thin film threshold switch device and a preparation method thereof.
In order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows:
the invention provides a preparation method of a barium titanate single crystal epitaxial film threshold switch device, wherein the structure of the device is Au/Cr/BTO/NSTO/In. The method comprises the following steps:
(1) ultrasonically cleaning a strontium niobate-doped titanate single crystal (NSTO) substrate for 5 minutes by respectively using acetone, absolute ethyl alcohol and deionized water in sequence;
(2) the washed NSTPlacing the O substrate into a Pulsed Laser Deposition system (Pulsed Laser Deposition), adjusting the distance between the target and the substrate, sealing the Pulsed Laser Deposition system, vacuumizing to a background vacuum, introducing high-purity oxygen to a specified pressure, raising the substrate temperature to a set temperature, selecting a proper BTO growth condition, and carrying out BaTiO growth3Growing the film, carrying out in-situ annealing after the growth is finished, cooling to room temperature under the protection of oxygen atmosphere, and taking out a sample;
(3) covering a mask plate on the surface of the barium titanate film, and evaporating a chromium (Cr) film;
(4) performing thermal evaporation on the chromium film to form metal Au;
(5) and pressing metal indium wires or indium grains on the back of the substrate to form ohmic contact with the NSTO substrate to be used as a lower electrode, thus obtaining the single crystal epitaxial barium titanate film threshold switch device, wherein the structure of the device is Au/Cr/BTO/NSTO/In.
According to the above preparation method, preferably, the strontium titanate niobium-doped single crystal substrate in step (1) is a commercial substrate with a (100) crystal face and a niobium doping amount of 0.7 wt%.
According to the above production method, preferably, the growth conditions in the step (2) are: the distance between the target and the substrate is 5 cm and 2.0 multiplied by 10-4 Pa background vacuum degree; 1 Pa oxygen pressure; the substrate temperature is 700 ℃; laser energy 300 mJ; laser repetition frequency: 5 Hz; the growth time is 15 minutes; and annealing in situ for 10 min.
According to the preparation method, preferably, in the step (3) and the step (4), the BaTiO3/NSTO heterojunction is placed in an electron beam evaporation and resistance evaporation composite coating system TEMD500 evaporation plating instrument, and the evaporation plating system is pumped to the background vacuum of 6 x 10-4 Pa, setting the current of a cathode filament of the electron gun to be 0.6A, preheating for 2 min for degassing, then opening a crucible baffle, carrying out electron beam evaporation and Au thin film thermal evaporation on the metal Cr thin film, and observing the film thickness in situ by using a quartz crystal oscillator.
According to the barium titanate single crystal epitaxial thin film threshold switch device prepared by the preparation method, the thickness of the chromium thin film is 5 nm, the thickness of the Au film is 50 nm, and the thickness of the metal electrode is 0.2 mm.
The invention has the following positive beneficial effects:
(1) the invention prepares a threshold switch device of a barium titanate single crystal epitaxial film with a multilayer structure under the vacuum condition for the first time, a layer of metal Cr film is additionally added to a common BTO film structure In the device, and the device is changed from bipolar resistance change characteristic to stable negative voltage threshold switch characteristic due to the metal Cr film, so that compared with the traditional conventional metal (Pt, Au)/BTO/NSTO/In, the single crystal barium titanate film device has good and stable threshold switch characteristic. Moreover, the single crystal barium titanate epitaxial thin film threshold switch device of the invention has stable VthAnd VholdThe distribution is expected to be widely applied to the field of selectors of RRAMs and novel nerve synapse bionic electronic devices in nanosecond-level switching time.
(2) The threshold voltage and holding voltage repeatability of the existing polycrystalline BTO thin film threshold switch device is poor. The preparation method of the barium titanate single crystal epitaxial film threshold switch device can obtain the voltage threshold switch characteristic with high repetition rate, has simple steps and easy operation, and the voltage threshold switch phenomenon of the invention is stable, so the barium titanate single crystal epitaxial film threshold switch device has high preparation success rate, has obvious and stable threshold switch characteristic, and is easy to realize the switch device with stable threshold switch characteristic.
Drawings
FIG. 1 is an XRD spectrum of a barium titanate single crystal thin film according to the present invention;
FIG. 2 is a diagram of threshold switch current-voltage for a barium titanate single crystal thin film device of the present invention;
FIG. 3 is a graph of threshold switch cycling stability of a barium titanate single crystal thin film device of the present invention;
fig. 4 is a diagram showing the switching response time of the barium titanate single crystal thin film device of the present invention.
Detailed Description
The present invention is further described in detail by the following specific examples, which are not intended to limit the scope of the present invention, and the process methods in the examples are conventional methods or procedures unless otherwise specified.
Example 1
A preparation method of a barium titanate single crystal epitaxial film threshold switch device is provided, the structure of the strontium titanate niobium-doped device is Au/Cr/BTO/NSTO/In, and the method comprises the following steps:
(1) respectively and sequentially carrying out ultrasonic cleaning on a strontium niobate-doped titanate single crystal (NSTO) substrate for 5 minutes by using acetone, absolute ethyl alcohol and deionized water, wherein the strontium niobate-doped titanate single crystal substrate is a commercial substrate with a (100) crystal face and a niobium doping amount of 0.7 wt%;
(2) the cleaned NSTO substrate with size of 5 mm × 3 mm was placed in a Pulsed Laser Deposition system (Pulsed Laser Deposition) using BaTiO with purity of 99.99% purchased from Mitsui New Material science and technology Co., Ltd, Beijing3Ceramic target material, regulating the distance between the target material and the substrate to 5 cm, sealing the pulsed laser substrate system and pumping to background vacuum of 2.0 × 10-4 Pa, then filling high-purity oxygen with the purity of 99.999 percent to the oxygen pressure (partial pressure of the oxygen) of 1 Pa, raising the temperature of the substrate to 700 ℃, and enabling the laser energy to be 300 mJ; laser repetition frequency: 5 Hz, on BaTiO3Growing the (BTO) film for 15 minutes, carrying out in-situ annealing for 10 min after the growth is finished, cooling to room temperature under the protection of oxygen atmosphere, and taking out a BTO film sample, wherein the thickness of the BTO film is about 50 nm;
(3) covering the NSTO sample with BTO film on a mask plate with square holes of 0.2 mm × 0.2 mm, placing into a TEMD500 evaporation plating apparatus of electron beam evaporation and resistance evaporation composite coating system, and pumping the evaporation plating system to a background vacuum of 6 × 10-4 Pa, setting the filament current of a cathode of an electron gun to be 0.6A, setting the filament voltage to be 140V, preheating for 2 min for degassing, then opening high pressure, focusing an electron beam on a target material in a crucible, slowly adjusting an evaporation adjusting knob to melt the target material, opening a target material baffle, performing electron beam evaporation on a metal Cr film, observing the film thickness in situ by using a quartz crystal oscillator, and controlling the thickness of the Cr film to be 5 nm;
(4) turning off an electron gun power supply of the TEMD500 evaporation instrument, turning on a thermal evaporation control power supply, setting the voltage to be 100V, waiting for Au to melt until the film forming rate on a film thickness detector reaches a required value, turning on a crucible baffle, starting thermal evaporation to form a metal electrode Au, observing the film thickness in situ by using a quartz crystal oscillator, and controlling the Au film thickness to be 50 nm;
(5) and (4) pressing a metal indium wire with the diameter of 1mm and the length of 2mm on the back surface of the substrate after the treatment In the step (4), wherein the thickness of the metal indium wire is about 0.2 mm, so that the metal indium wire and the NSTO substrate form ohmic contact to be used as a lower electrode, and the single crystal epitaxial barium titanate film threshold switch device is obtained, and the structure of the device is Au/Cr/BTO/NSTO/In.
The X-ray diffraction pattern of the barium titanate thin film prepared in step (2) is shown in fig. 1, and fig. 1 shows that it is a single crystal epitaxial thin film.
The electrical property tests of the single crystal epitaxial barium titanate thin film threshold switch device are all performed In an atmospheric environment, probes are used for contacting an upper electrode Au and a lower electrode In of the device, a Keithley2400 source table is used for carrying out current-voltage scanning, only negative bias voltage is applied, appropriate limiting current is set to prevent the device from being damaged, a stable negative threshold switch is obtained, and the result is shown In figure 2. As can be seen from FIG. 2, when scanning from 0V to-9V, the device transits from the high resistance state to the low resistance state at around-5V, and this transition voltage is called the threshold voltage Vth(ii) a And when scanning from-9V to 0V, the device transits from the low-resistance state to the high-resistance state at about-3V, and the transition voltage is called as a holding voltage Vhold。
The statistical results of threshold and holding voltage are shown in fig. 3 after 1000 weeks of testing in an atmospheric environment. As can be seen from FIG. 3, the threshold voltage is stabilized at-5.07 + -0.12V, and the holding voltage is stabilized at-3.12 + -0.08V, so that the threshold voltage and the holding voltage can be stabilized for 1000 weeks.
The switching time test of the barium titanate single crystal epitaxial film threshold switch device is carried out by contacting an upper electrode Au and a lower electrode In of the device with a probe and connecting a resistance load R with the resistance value of 100 omega0The signal generator Keysight 33600 and the oscilloscope Keysight DSOX3024T are respectively connected with the upper electrode and the lower electrode of the device, the signal generator applies pulses, the oscilloscope respectively measures the output voltage of the signal generator and the voltage obtained by dividing the output voltage of the series resistor, and then the data of the switching time of the device is obtained, and the connection circuit is shown as a figure 4 (a). Black line corresponding Signal Generator output in FIG. 4(b)The signal, and the red line corresponds to the voltage signal on the series resistance of the resistive switching device, and the time difference between the two lines corresponds to the response time of the device. The time difference on the left side corresponds to the on-time, and the time difference on the right side corresponds to the off-time. Due to the limitation of the bandwidth of the oscilloscope, the turn-on time of the device is not more than 25.6 ns, and the turn-off time is not more than 23.2 ns, and the result is shown in fig. 4 (b).
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalents thereof, without departing from the scope thereof, by applying the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiment example according to the technical essence of the present invention are still within the protection scope of the technical solution of the present invention, unless the technical essence of the present invention departs from the content of the technical solution of the present invention.
Claims (5)
1. A method for preparing a barium titanate single crystal epitaxial film threshold switch device comprises the following steps:
(1) taking NSTO as a substrate, putting the cleaned NSTO substrate into a pulse laser deposition system, taking barium titanate ceramic as a target material, growing a barium titanate film, carrying out in-situ annealing after the growth is finished, cooling to room temperature under the protection of oxygen atmosphere, and taking out a sample;
(2) covering a mask plate on the surface of the barium titanate film, and evaporating a Cr film;
(3) then performing thermal evaporation on the Cr film to form a metal Au film;
(4) and pressing metal indium wires or indium grains on the back of the substrate to be used as a lower electrode to obtain the single crystal epitaxial barium titanate film threshold switch device, wherein the structure of the device is Au/Cr/BTO/NSTO/In.
2. The method for preparing a barium titanate single crystal epitaxial thin film threshold switching device according to claim 1, wherein in the step (1), the NSTO substrate is a commercial substrate with a (100) crystal face and a niobium doping amount of 0.7 wt%.
3. The method for preparing a barium titanate single crystal epitaxial thin film threshold switching device according to claim 1, wherein the growth conditions in step (1) are: the distance between the target and the substrate is 5 cm and 2.0 multiplied by 10-4 Pa background vacuum degree; 1 Pa oxygen pressure; the temperature of the substrate is 700 ℃; laser energy 300 mJ; laser repetition frequency: 5 Hz; the growth time is 15 minutes; annealing in situ for 10 minutes.
4. The method for preparing a threshold switching device of a barium titanate single crystal epitaxial thin film according to claim 1, wherein in the step (2), the NSTO substrate of the barium titanate thin film is placed in an evaporation apparatus, and the evaporation system is pumped to a background vacuum of 6 x 10-4 Pa, setting the current of a cathode filament of the electron gun to be 0.6A, preheating and degassing, then opening a crucible baffle, carrying out electron beam evaporation on the metal Cr film, and observing the film thickness in situ by using a quartz crystal oscillator.
5. The barium titanate single crystal epitaxial thin film threshold switching device manufactured by the manufacturing method of any one of claims 1 to 4, wherein the thickness of the barium titanate thin film is 50 nm, the thickness of the Cr thin film is 5 nm, and the thickness of the Au thin film is 50 nm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911257017.4A CN110970554B (en) | 2019-12-10 | 2019-12-10 | Barium titanate single crystal epitaxial film threshold switch device and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911257017.4A CN110970554B (en) | 2019-12-10 | 2019-12-10 | Barium titanate single crystal epitaxial film threshold switch device and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110970554A CN110970554A (en) | 2020-04-07 |
| CN110970554B true CN110970554B (en) | 2021-03-19 |
Family
ID=70033553
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911257017.4A Active CN110970554B (en) | 2019-12-10 | 2019-12-10 | Barium titanate single crystal epitaxial film threshold switch device and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110970554B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111525029B (en) * | 2020-06-04 | 2023-09-22 | 河北大学 | Pd conductive filament-based bionic synaptic device and preparation method and application thereof |
| CN113707806A (en) * | 2021-08-26 | 2021-11-26 | 山东大学 | Long-range plasticity ferroelectric tunnel junction nerve synapse device with high symmetry and high linearity as well as preparation method and application thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7102858B2 (en) * | 2002-02-18 | 2006-09-05 | Alps Electric Co., Ltd. | Thin-film electrode layer including β-ta and thin-film magnetic head using the same |
| US9178131B2 (en) * | 2008-12-02 | 2015-11-03 | Drexel University | Ferroelectric nanoshell devices |
| CN109346599A (en) * | 2018-09-26 | 2019-02-15 | 中国科学技术大学 | More iron tunnel knot memristors and preparation method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20190131384A1 (en) * | 2017-10-27 | 2019-05-02 | National University Of Singapore | Ferroelectric tunnel junction structure and method of fabricating the same |
-
2019
- 2019-12-10 CN CN201911257017.4A patent/CN110970554B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7102858B2 (en) * | 2002-02-18 | 2006-09-05 | Alps Electric Co., Ltd. | Thin-film electrode layer including β-ta and thin-film magnetic head using the same |
| US9178131B2 (en) * | 2008-12-02 | 2015-11-03 | Drexel University | Ferroelectric nanoshell devices |
| CN109346599A (en) * | 2018-09-26 | 2019-02-15 | 中国科学技术大学 | More iron tunnel knot memristors and preparation method thereof |
Non-Patent Citations (5)
| Title |
|---|
| Compliance current and film thickness influence upon multi-level threshold resistive switching of amorphous BaTiO3 (am-BTO) films in Ag/am-BTO/Ag cross point structures;Razi P M , Gangineni R B;《Thin Solid Films》;20190528;第685卷;全文 * |
| Enhanced tunnelling electroresistance effect due to a ferroelectrically induced phase transition at a magnetic complex oxide interface;Yin Y W , Burton J D , Kim Y M;《Enhanced tunnelling electroresistance effect due to a ferroelectrically induced phase transition at a magnetic complex oxide interface》;20130217;第12卷(第5期);全文 * |
| Ferroelectric Field Effect Induced Asymmetric Resistive Switching Effect in BaTiO3/Nb:SrTiO3 Epitaxial Heterojunctions;Jia C , Li J , Yang G , et al;《Nanoscale Research Letters》;20180413;第13卷;全文 * |
| 钛酸钡/镍酸钐异质结的阻变机理研究;贾梅秀;《中国硕士论文全文库基础科学辑》;20190930;全文 * |
| 铁电忆阻器在神经形态应用的研究;蒋真正;《中国硕士论文全文库工程科技Ⅱ辑》;20190131;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110970554A (en) | 2020-04-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Huang et al. | Amorphous ZnO based resistive random access memory | |
| Wang et al. | Multilevel resistive switching in Ti/CuxO/Pt memory devices | |
| CN110970554B (en) | Barium titanate single crystal epitaxial film threshold switch device and preparation method thereof | |
| US6759249B2 (en) | Device and method for reversible resistance change induced by electric pulses in non-crystalline perovskite unipolar programmable memory | |
| CN108807668B (en) | High-performance memristor based on metal oxide oxygen concentration gradient and preparation thereof | |
| CN108365089A (en) | Prepared by a kind of solution combustion method has analog- and digital- multi-functional NiO bases memory resistor and preparation method | |
| Shin et al. | Effect of program/erase speed on switching uniformity in filament-type RRAM | |
| CN104409630A (en) | Unipolar resistive random access memory based on gallium oxide thin film, and preparation method for unipolar resistive random access memory | |
| CN107895757A (en) | A kind of nano dot contact of quantum conductance controlled properties | |
| JP2004241396A (en) | Method for manufacturing resistance varying element, method for manufacturing nonvolatile resistance varying memory device, and nonvolatile resistance varying memory device | |
| CN109950394A (en) | The method that no electric forming process resistance-variable storing device realizes quantum conductance effect | |
| Liu et al. | Resistance switching properties of sol–gel derived SrZrO3 based memory thin films | |
| CN109461814B (en) | Memristor based on zinc oxide, preparation method of memristor and application of memristor in preparation of neurosynaptic biomimetic device | |
| CN105098065B (en) | A kind of preparation method of storage unit of resistive random access memory (RRAM) and products thereof | |
| CN111223986B (en) | Silver intercalation gating device based on hafnium oxide transition layer and manufacturing method thereof | |
| CN102623637B (en) | Resistive random access memory (RRAM) with electrically conductive channels formed controllably and producing method thereof | |
| CN109461813B (en) | Resistive random access memory based on tungsten sulfide nanosheet and preparation method thereof | |
| CN101969100A (en) | Nonvolatile resistance-variable storage and preparation method thereof | |
| CN112018236A (en) | PZT-based memristor device, and preparation method and application thereof | |
| An et al. | Effects of thermal annealing on analog resistive switching behavior in bilayer HfO 2/ZnO synaptic devices: the role of ZnO grain boundaries | |
| Wang et al. | Effects of electrode on resistance switching properties of ZnMn 2 O 4 films deposited by magnetron sputtering | |
| CN114203918B (en) | Novel photoelectric memristor based on PVK/ZnO heterostructure | |
| CN117729840A (en) | High-flux iron resistance variable device and preparation method thereof | |
| Mondal et al. | Transient memory and learning in correlated oxide neuromorphic devices | |
| Dai et al. | Synaptic-like conductivity and plasticity in epitaxially strained SrTiO3 films |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |