Atom Nanopositioning Device

Abstract

A nanopositioning system for fine and coarse nanopositioning is provided, comprising at least one actuator, the at least one actuator comprising a high Curie temperature material, and the nanopositioning system is configured to apply a voltage to the at least one actuator to cause fine and / or coarse motion by the at least one actuator. The nanopositioning system may be a stand-alone system, a scanning probe microscope, or an attachment to an existing microscope configured to perform a creepless nanopositioning method, including positioning a probe relative to a first area of ​​a substrate using coarse stepping and interacting with the first area of ​​the substrate using fine motion less than 60 seconds after positioning the probe. The operation of the scanning probe microscope is actuated by a high Curie temperature piezoelectric material that limits and / or eliminates creep, hysteresis, and aging.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 893,338, filed Aug. 29, 2019, which is incorporated herein by reference.

[0002] The present invention is directed to the field of nanopositioning systems, and more particularly to the field of piezoelectric actuators, including piezoelectric nanopositioning systems for scanning probe microscopy. [Background technology]

[0003] As the miniaturization of complementary metal-oxide-semiconductor (CMOS) technology approaches its fundamental limits, alternative methods constructed at the atomic level, such as that disclosed in U.S. patent application Ser. No. 16 / 318,262, are being developed. 1、2、3

[0004] Scanning probe microscopes (SPMs) are a group of tools used to create images of nanoscale surfaces and structures, including atoms. They use a physical probe to scan back and forth over the surface of a sample. During this scanning process, a computer collects data that is used to create an image of the surface. There are several types of SPMs. Some examples include atomic force microscopes, magnetic force microscopes, and scanning tunneling microscopes. An atomic force microscope (AFM) measures the force between a cantilever tip and the sample. A magnetic force microscope (MFM) measures magnetic force. A scanning tunneling microscope (STM) measures the tunneling current that flows between the tip and the sample.

[0005] SPMs have a probe tip that can be as sharp as a single atom. The tip moves back and forth across a surface with precision and accuracy, even down to a single atom. When the tip is near the sample surface, the SPM can measure tip-surface interactions caused by a variety of effects, including tunneling currents, electrostatic forces, magnetic forces, chemical bonds, van der Waals forces, and capillary forces. SPMs can detect height differences that are a fraction of a nanometer, roughly the diameter of a single atom. A computer combines the data to create an image.

[0006] In addition to visualizing nanoscale structures, SPMs are used to manipulate individual atoms and molecules, moving them to create specific patterns.

[0007] Scanning probe microscopy (SPM) has demonstrated spin-based logic using Fe atoms on a Cu(III) surface. 4 , Single-atom transistors using phosphorus dopants in silicon 5 , and binary atomic wires and logic gates using dangling bonds (DB) on hydrogen-terminated silicon (H-Si) 6 Hydrogen desorption on H-Si surfaces enables the fabrication of DB-based circuits for the next generation of extremely miniaturized, low-power nanoelectronic devices beyond complementary metal-oxide-semiconductor (CMOS) technology.

[0008] Hydrogen-terminated silicon surfaces are promising platforms for atomic circuits and binary data storage at the atomic scale. This is due, among other things, to their inertness, thermal stability, very low defect density, and in particular the unique properties of their surface dangling bonds. The fundamental properties of the insulated dangling bonds have been extensively studied. They are electronically isolated from the host substrate and have been shown to be capable of carrying a charge, thus acting as atomic quantum dots. They can be precisely positioned and erased, i.e., to the state 0 or 1. Various functional elements such as quantum-cellular-automaton cells, binary transmission lines, and binary computation gates can be fabricated by placing dangling bonds close to each other. Dangling bonds on H-Si surfaces can be rewritten. 11、12、13 And stable at room temperature 14、15 It has been shown that these materials have excellent properties, making them excellent candidates for atomic-scale devices.

[0009] The H-Si surface is characterized by the self-determined growth of ordered molecular beams. 16、17 and reaction energetics 18 It has found applications in the study of surface chemistry, including the controllable desorption of hydrogen from a H-Si(100)-2×1 surface using the probe tip of a scanning tunneling microscope (STM). 19 allows for more precise investigation of surface chemistry 20 and the manufacture of elementary devices 21、22 With the continued research of DBs on H-Si surfaces, more complex and feasible devices are being developed.

[0010] In principle, the capabilities of this technology will provide smaller, more efficient, faster, and cheaper electronic devices than the currently dominant CMOS technology. Despite advances in the design of these and other device concepts, 7、8、9、10 ,Practical implementation is limited due to limitations of existing SPMs and scanners.

[0011] Current scanners for SPMs tend to experience creep when the scanner is repositioned or if it is moved too quickly during a scanning operation. Creep is a variant of the electric field-driven ferroelectric poling process. All scanners are poled by applying an electric field while heating the scanner above the Curie temperature. The field is maintained until the scanner material cools, thereby trapping remnant polarizations even when the applied field is zero. However, actuating the scanner even well below the Curie temperature induces some degree of undesirable repoling, resulting in a nonlinear behavior known as creep. Creep is most obvious and most troublesome each time a new scan area is selected. This is true whether the new area is reached by repositioning the SPM's fine scanner, or whether the new location is selected through the use of the SPM's coarse X,Y (inertial) motors or during the initial Z approach to the sample with the coarse motors and / or fine scanner.

[0012] When the probe is moved to a new area, creep can cause drift effects lasting up to several minutes, distorting the scanned image and causing subsequent scans to be of substantially shifted areas with distortions in Z. In routine scanning, delays of several minutes are typically required to acceptably minimize this asymptotic behavior. The most precise measurements, requiring picometer-level accuracy, require scanner downtime periods of the order of several hours before measurements can begin. Creep can also be evident when large changes in the slow scan direction occur, for example when restarting the scan of successive images. Creep is also evident after the probe approaches the surface, because the Z range is usually extended to its maximum. This requires a significant amount of time to eliminate creep in the Z direction.

[0013] Closed-loop scanners can compensate for creep, but they are complex and require additional real estate for the scanner assembly. Furthermore, closed-loop scanners are expensive and often require reduced scan speeds if the highest level of accuracy is required. Loop scanners may also result in lower positioning resolution due to their feedback circuits and operation. Creep can be significantly reduced by working at 4K, but for most applications the additional expense of cryogenic operation is simply impractical. In the most demanding cases where there is no choice but to work at 4K, measurement limitations due to creep remain. Creep has become accepted as unavoidable in SPM, limiting the accuracy, efficiency, and applicability of the technique.

[0014] Creep is also present in coarse positioning using shear piezoelectrics in stick-slip mode; i.e., in shear piezoelectric stick-slip motion with inertial actuators, creep may occur after the stick-slip motion. Creep may also occur in fine positioning of shear plate motors, which is similar to the creep caused by scanning as described above. In these situations, a closed loop is required to correct for creep, and the usual issues with closed loop systems apply (see above). Although the amount of creep exhibited in these situations is small compared to the type of motion being measured, creep is still present. However, in the existing literature, creep effects are largely ignored (piezoelectric actuators (PA) work at high frequencies in piezoelectric inertial friction actuator (PIFA) systems, where creep effects are small). In operations such as micron-scale hysteresis and capacitance position sensor studies, which have low resolution, the effects of creep are ignored. However, creep occurs without exception and, as a scale issue, cannot be ignored in high-resolution applications such as atomic-scale manufacturing.

[0015] Furthermore, piezoelectric actuators exhibit "aging" and are limited with respect to their operating temperature. Aging is related to depoling. Furthermore, the displacement of some piezoelectric materials (PZT) is frequency dependent due to creep and hysteresis. Thus, the displacement of a single step may vary depending on the ramp rate and the amplitude of the triangle wave. Summary of the Invention [Problem to be solved by the invention]

[0016] Thus, there is a need for a system and method for SPM that eliminates creep effects in all three axes, both after repositioning of the fine scanner and after repositioning using the coarse motor, thereby providing faster and cleaner scans in a commercially viable manner. Additionally, there is a need for piezoelectric actuators that do not exhibit aging as a result of depoling, have limited hysteresis, and can withstand high temperature scanning without issue. Creep-free motion is also desirable in other applications requiring high-resolution positioning, such as optical lithography, optical mirror positioning, SEM imaging, and sensing.

[0017] Furthermore, when using tube scanners, barrel distortion may be observed in the images due to the bending motion of the tube as it scans in XY, which affects the measured Z. To mitigate this barrel effect, tube scanners are usually forced to scan within a small range of the scanner limits.

[0018] Therefore, a need exists to create a nanopositioning system that scans XY through its limits while limiting the effects of Z. [Means for solving the problem]

[0019] The present invention provides a nanopositioning system for fine and coarse nanopositioning comprising at least one actuator, the at least one actuator comprising a high Curie temperature material, the nanopositioning system configured to apply a voltage to the at least one actuator to produce fine and / or coarse motion by the at least one actuator. The nanopositioning system may be a stand-alone system, a scanning probe microscope, or an attachment to an existing microscope configured to perform a creepless nanopositioning method including positioning a probe relative to a first area of ​​a substrate using coarse stepping, and interacting with the first area of ​​the substrate using fine scanning less than 60 seconds after positioning the probe. The scanning probe microscope motion is actuated by a high Curie temperature piezoelectric bimorph activated by an applied voltage. The scanning probe microscope motion is secondary to the applied voltage. Alternatively, the scanning probe microscope motion is actuated by a high Curie temperature piezoelectric material that limits and / or eliminates creep, hysteresis, and aging. The present invention includes both coarse motion by stick-slip actuation and fine motion using shear piezoelectrics. Fine scanning and coarse motion can also be actuated using a bimorph implementation in which a piezoelectric bends with an applied voltage to impose directional motion at the non-fixed end of the bimorph. A crawler implementation advances the motor continuously and without mechanical or electrical shock by advancing each of three or more directional actuators in sequence, one at a time. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 illustrates an actuator of a nanopositioning system according to an embodiment of the present disclosure comprising multiple lithium niobate shear piezoelectric crystals separated by metal plates. [Diagram 2]FIG. 2 is a diagram showing a stationary stage of a nanopositioning system according to an embodiment of the present disclosure, the stationary stage comprises three actuators connected by one electrode for applying a voltage and a ceramic ball that rests on the V-groove and plate of the motion stage of FIG. 3, positioned on the electrode, the stationary stage also has two disk magnets embedded therein for magnetically fastening the motion stage of FIG. 3 to the stationary stage. [Diagram 3] FIG. 3 illustrates a translation stage of a nanopositioning system according to an embodiment of the present disclosure, which includes a V-groove and a flat plate that mounts the three ceramic balls of FIG. 2 and allows single-axis motion. [Figure 4] FIG. 4 is a perspective view illustrating an assemble mover of a nanopositioning system according to an embodiment of the present disclosure. [Figure 5A-5B] Figures 5A and 5B show room temperature scanning tunneling microscope images of a silicon 100 surface using a conventional scanner, where Figure 5A shows a scan image of the surface at a first position and Figure 5B shows a scan image of the surface after 80 nm of lateral movement of the scanner. Figure 5B shows significant creep as evidenced by the curvilinear appearance of the row features compared to Figure 5A. [Fig. 5C-5D] Figures 5C and 5D show room temperature scanning tunneling microscope images of a silicon 100 surface using a scanner according to an embodiment of the present disclosure, with Figure 5C showing a scanned image of the surface at a first position and Figure 5D showing a scanned image of the surface after 80 nm of lateral movement of the scanner. In Figure 5D, the columns appear straight rather than curved, and furthermore, the slope of the columns is the same as in Figure 5C, which was taken before repositioning. [Figure 6]FIG. 6 is a graph showing creep rate versus time for a conventional scanner (curve) and a creep-free scanner according to an embodiment of the present disclosure (straight line), where the conventional scanner line shows that the conventional scanner continues to move (creep) despite a constant control signal, resulting in severe warping of the scanned image of FIG. 5B obtained after repositioning the probe, and an undesirable shift of the scanned area as the scan progresses, while the creep-free scanner line according to an embodiment of the present disclosure shows that the probe moves as commanded and does not creep, allowing an image to be recorded immediately after repositioning the probe, instantly giving an accurate usable scan as shown in FIG. 5D. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] definition

[0022] As used herein, "high Curie temperature piezoelectric material" refers to a piezoelectric material having a Curie temperature above 600° C. Examples of high Curie temperature piezoelectric materials include, but are not limited to, lithium niobate, lithium tantalite, PbTiNb2O8, PbZrNb2O8, and CaBi2Nb2O9.

[0023] As used herein, the term "fine motion" refers to the movement or displacement of a piezoelectric actuator in contact with an object, such as a stage, that is stationary relative to the piezoelectric actuator, where the point of contact between the piezoelectric actuator and the stationary object is fixed and does not change as the piezoelectric actuator moves.

[0024] As used herein, "coarse motion" refers to movement of the piezoelectric actuator in contact with an object, such as a stage, that is stationary relative to the piezoelectric actuator, and the contact point between the piezoelectric actuator and the stationary object changes with the movement of the piezoelectric actuator, i.e., the contact point is not fixed. Movement of the piezoelectric actuator relative to the stationary object occurs in discrete steps, and the contact point between the piezoelectric actuator and the stationary object changes as the piezoelectric actuator moves.

[0025] As used herein, the term "substantially" refers to the qualitative state of exhibiting a desired feature or characteristic to a complete or nearly complete extent or degree. For example, being substantially free of a feature or characteristic means that the feature or characteristic is either completely absent or present to a sufficiently low degree that it has either no effect or only a minor effect on the intended performance or properties.

[0026] As used herein, the terms "creepless" and "hysteresis-free" scanning or positioning refer to scanning or positioning that is substantially devoid of creep or hysteresis.

[0027] explanation

[0028] The present invention has utility as a system and method for scanning probe microscopy (SPM) and as a nanopositioning system that substantially eliminates creep effects and limits hysteresis and aging in all three axes, both after repositioning of the fine scanner and after repositioning using the coarse motor, thereby providing faster and cleaner scans in a commercially viable manner. Coarse motor positioning can also be more repeatable because creep, hysteresis, and aging are limited by providing consistent steps as a function of frequency and voltage that are not achievable using standard piezoelectric materials. 23 .

[0029] Crystalline silicon is tetravalent and forms a diamond-type crystal lattice. Each silicon atom shares four bonds, two above the atom and two below it. At the surface, two of these bonds are unsaturated, so the crystal rearranges into a lower energy configuration. During the annealing process, the addition of hydrogen atoms to the silicon surface results in the formation of one of three possible phases. The possibility of forming these phases can be controlled by the annealing temperature at which the sample is prepared. The 2x1 phase forms at approximately 300-350°C, the 3x1 phase forms at approximately 100-150°C, and the 1x1 phase forms below about 20°C. 33、14、34 The most regularly used for DB patterning is the reconstruction of the 2×1 phase, where each surface atom pairs with a neighboring surface atom to create a dimer pair. The dimer pairs form in rows that run parallel to each other across the surface. Each silicon atom at the surface is left with a single unsaturated bond that extends into the vacuum space and can either be terminated with hydrogen or left vacant to create a dangling bond. Although the preparation of the H-Si(100)-2×1 phase is well understood, producing a perfectly clean, defect-free surface is often difficult. These defects, as well as the clean H-Si(100), can be imaged using STM.

[0030] The disclosed embodiments provide a nanopositioning system or scanner for scanning probe microscopy (SPM) applications that substantially eliminates creep effects in all three axes, both after repositioning of the fine scanner and after repositioning using the coarse motor. The SPM system, nanopositioning system, and method of the disclosure make SPM and positioning much more efficient by eliminating the delay time between changing position and starting a scan in a new area without distortion. According to an embodiment, the disclosure provides a creepless scanning probe microscopy (SPM) or nanopositioning method that includes positioning a probe of a scanning probe microscope relative to a first area of ​​a substrate, and scanning the first area of ​​the substrate less than 60 seconds after positioning the probe. Because the scanning or positioning systems and methods of the disclosure are creepless, scanning, reading, or writing can begin immediately after positioning or repositioning the probe, compared to the long delay and repoling times of conventional systems.

[0031] According to an embodiment, the creepless SPM system and method or nanopositioning system further includes recording an image of the scanned substrate with the SPM, where the recorded image eliminates image warping or distortion such as that shown in FIG. 5B and does not require the application of correction algorithms during or after data collection.

[0032] Embodiments of the present invention are simpler (and therefore more compact), less expensive, and less prone to failure than conventional closed-loop systems. Furthermore, the elimination of the closed loop reduces positioning noise and increases scanning speed in high-speed AFMs. According to embodiments of the present disclosure, the scanner / positioner is an accessory that is easily integrated as a plug-and-play module into existing SPM infrastructure, reducing the need for expensive development and facilitating widespread adoption.

[0033] By investigating the microscopic changes that occur during the poling process, the systems and methods of the present disclosure provide effective elimination of undesired poling during normal scanning, creating a near perfect scanner.Embodiments provide an atom beam scanner or nanopositioner that allows imaging and fabrication with significantly reduced errors while also saving time.

[0034] An embodiment of the creepless scanning / positioning system includes a fine motion scanner and / or an inertial translation device, also known as a stick-slip translation device. According to an embodiment, the motor and / or other components of the system are formed from a high Curie temperature ferroelectric material and are therefore substantially free of creep and hysteresis. According to a particular embodiment, in addition to the usual fine motion scanner and stick-slip type translation device, the system also includes a crawler that advances the motor continuously and without mechanical or electrical shocks by advancing each of the three or more directional actuators one by one in sequence. The crawler can perform very fine movements of picometer increments. In contrast to the inertial translation device, also known as a stick-slip translation device, the crawler can be considered a continuous motion device or a non-stick-slip device. According to an embodiment, the crawler is also made from a high Curie temperature ferroelectric material. The crawler offers the added advantage of moving very smoothly without the vibratory impulsive action of conventional inertial translators and without the associated large and fast swings in the control voltage. Such mechanical and electrical perturbations associated with any inertial translator have detrimental noisy effects on sensitive instruments and measurements made with them. Crawlers effectively reduce that noise and perturbations. To move smoothly, continuously, and not step-by-step, crawlers require more complex control signals and finer mechanical tolerances. For example, the actuators of the crawlers smoothly contract in length, and thereafter all actuators equally and simultaneously extend to achieve sample motion. When fully extended, the process is repeated, with each actuator contracting in turn, causing slippage between the actuator and the sample / moving stage it drives in order to reposition that actuator's contact point. Due to the greater friction between the other actuators, the driven moving stage remains stationary. The process is repeated until each actuator has a new contact point, enabling the motion of the moving stage. The sequence of each actuator can be timed to provide smooth motion without the vibration or shock of a conventional inertial translator.

[0035] According to an embodiment, the present invention also provides a long-range fine scanner based on the bimorph concept. A bimorph is a sandwich-type actuator formed by bonding two layers of piezoelectric material together, often with a support layer disposed between the two piezoelectric layers. A bimorph is two piezoelectric materials bonded together, and when a voltage is applied, one piezoelectric layer expands while the other contracts, resulting in bending deformation. The bending motion is at an angle to the expansion / contraction of the piezoelectric material in the bimorph and is much larger than the linear length change of either piezoelectric material. The motion is approximately quadratic to the voltage. According to an embodiment, a bimorph of a high Curie temperature piezoelectric material such as lithium niobate achieves the desired creep-free motion. According to an embodiment, the present invention provides a 2D scanning assembly of two or more high Curie temperature piezoelectric bimorphs. According to an embodiment, a 3D scanning assembly includes a combination of three (or more) bimorphs that allows scanning in the X, Y, and Z directions. These 2D and 3D scanners have excellent creep-free characteristics. These 2D and 3D scanners also achieve relatively large scanning ranges compared to simple linear or shear actuators. According to embodiments, the range is approximately 100 microns in X and Y, and 1-10 times less in Z. In embodiments, the range is up to 250 microns in X and Y.

[0036] In an embodiment, a ferroelectric material is used that has a Curie temperature much higher than commonly applied materials such as lead zirconate. Conventional scanner materials typically have a Curie temperature between 200 and 350°C. In contrast, the high Curie temperature piezoelectric materials utilized in the present invention have a Curie temperature greater than 600°C. In one embodiment, the high Curie temperature material has a Curie temperature of about 1200°C. The high Curie temperature material can be a ferroelectric material. Those skilled in the art will appreciate that high Curie temperature piezoelectric materials such as lithium niobate, lithium tantalite, PbTiNb2O8, PbZrNb2O8, and CaBi2Nb2O9 can provide similar creepless behavior.

[0037] According to an embodiment, the present invention also provides a nanopositioning system 10 configured to provide both fine and coarse positioning (motion). In one embodiment, the nanopositioning system comprises at least one actuator 12, the at least one actuator comprising a high Curie temperature material, and the nanopositioning system is configured to apply a voltage to the at least one actuator to cause fine motion by the at least one actuator. In an embodiment, the nanopositioning system is further configured to apply a voltage to the at least one actuator to cause coarse motion by the at least one actuator. For example, a shear actuator may be operated in a shear mode to cause fine motion or in a slip-stick mode to cause coarse motion. Other actuators that can be operated to cause fine or coarse motion depending on how the voltage is applied include bimorph actuators and longitudinal actuators. For example, the speed at which the voltage is changed / applied and the shape of the voltage curve (e.g. triangular or sawtooth) can be varied, thereby changing the operation mode from coarse to fine.

[0038] FIG. 1 shows an actuator 12 of a nanopositioning system 10 according to an embodiment of the present disclosure, comprising a number of lithium niobate shear piezoelectric crystals 14 separated by metal plates 16. FIG. 2 shows a stationary stage 18 of the nanopositioning system 10, comprising three actuators 12 connected by an electrode 20 for applying a voltage and a ceramic ball 22 that rests on a V-groove 24 and a plate 26 of a translation stage 28 of FIG. 3, disposed on the electrode 20. The stationary stage 18 also has two disk magnets 30 embedded therein for magnetically fastening the translation stage 28 of FIG. 3 to the stationary stage 18. The translation stage 28 is shown in FIG. 3, comprising a V-groove 24 and a flat plate 26 that rests on the three ceramic balls 22 of FIG. 2, allowing movement in one axis, e.g., the x-axis. FIG. 4 shows a perspective view of an assembled two-axis mover of the nanopositioning system 10. In the assembled mover of Figure 4, the x-axis actuator is located to the side of the stationary (middle) stage 18 and the y-axis actuator is located on the opposite side of the stationary (middle) stage 18. The upper and lower stages are the two moving stages 28, 28'. The bottom stage 28' of the mover is bolted to a stationary object, so the middle stage 18 and upper stage 28 provide the x and y motion for the mover.

[0039] In other embodiments, the nanopositioning system comprises at least one actuator for fine movement and at least one second actuator for coarse movement as described above, the at least one second actuator comprising a high Curie temperature material, and the nanopositioning system is configured to apply a voltage to the at least one second actuator to cause coarse stepping by the at least one second actuator. In an embodiment, the at least one actuator is a bimorph actuator, a shear actuator, or a longitudinal actuator. In an embodiment, the at least one second actuator is a bimorph, a shear, or a longitudinal actuator. The basic design and operation of these types of actuators will be understood by those skilled in the art. The nanopositioning system may comprise a single actuator capable of fine movement or both fine and coarse movement, or the nanopositioning device may comprise multiple actuators capable of fine movement or both fine and coarse movement. For example, the nanopositioning system may comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, or more actuators capable of fine movement or both fine and coarse movement. Similarly, in addition to the actuator(s) capable of fine or both fine and coarse motion, the nanopositioning device may comprise a single actuator capable of coarse motion, or may comprise multiple actuators capable of coarse motion. For example, the nanopositioning device may comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, or more actuators capable of coarse motion. The actuators capable of coarse motion are referred to herein as coarse motors. The number of actuators may be selected by one skilled in the art depending on the desired axis of motion and the mechanical design of the nanopositioning system. In one embodiment, a nanopositioning device for scanning probe microscopy comprises three actuators mounted on a stationary stage per axis. Each actuator is a stack of thin sheared lithium niobate piezoelectric crystals separated by a metal plate for applying a voltage to each face of the crystal. An alternating voltage through the metal plate allows a field to be applied through the crystal to produce a shear action.The crystals require the correct crystallographic orientation to produce a shear action in the applied voltage field, which is a function of how the crystals were cut from a bulk single crystal of lithium niobate. Above each actuator there is a ceramic ball resting in a V-groove for two actuators, and a ceramic ball resting on a flat plate for the third actuator. The V-grooves and plate are mounted within a moving stage. This allows for uniaxial motion. A quick drop (10 ns) in the applied field for all three actuators causes the moving stage to slip a small amount (a few nm to μm) for all three actuators, which constitutes one coarse step. If the fields of the three actuators are changed slowly (for microseconds), the ceramic balls will retain their location in the V-groove and plate, and the moving stage can scan back and forth in direct proportion to the field. This constitutes fine motion. Another set of actuators is mounted on the back of the stationary stage, acting on the V-grooves and plate mounted on the moving stage at right angles to the first set. This causes motion perpendicular to the first set when the second set of three actuators is actuated. This can be understood as x and y motion.

[0040] The nanopositioning systems of the present disclosure may find applications outside the field of scanning probe microscopy where fine and coarse nanopositioning with little to no creep or hysteresis is desired, such as positioning stages for SEMs, TEMs, alignment stages for semiconductor lithography and fine mirror and optical stage motion.

[0041] The following examples are illustrative, non-limiting examples of the present invention. The specific details provided in the examples should not be construed as limiting the scope of the appended claims. EXAMPLES

[0042] A room temperature scanning tunneling microscope is equipped with both a conventional scanner and a scanner according to an embodiment of the present disclosure to measure and compare the creep rate of each type of scanner. A silicon (100) sample is used for the comparative scan. The naturally occurring columns on the silicon (100) surface provide a convenient visual guide. The columns should appear as straight lines. After leaving the tip stationary for a long enough time to eliminate detectable creep motion, images are recorded using the conventional scanner and the scanner of the present disclosure. The image produced by the conventional scanner is shown in FIG. 5A, and the image produced using the scanner of the present disclosure is shown in FIG. 5C.

[0043] The tip is then repositioned 80 nm laterally and a new scan is immediately initiated. To eliminate operator-related timing variability, the movement and initiation of the new scan are under program control. FIG. 5B shows an image recorded by a conventional scanner after repositioning. FIG. 5D shows an image recorded by the scanner of the present disclosure after repositioning. As shown in FIG. 5B, the image recorded by the conventional scanner after repositioning contains distortion or curvature due to creep in the image. Furthermore, a comparison of the images recorded by the conventional scanner before (FIG. 5A) and after (FIG. 5B) repositioning shows a difference in the slope of the rows, indicating that creep has not yet fully subsided. As shown in FIG. 5D, the rows of the scan image recorded with the scanner of the present disclosure after repositioning appear straight instead of curved, and further, the slope of the rows is the same in the images taken before and after repositioning. Images were collected for approximately 1-30 min.

[0044] In this example, the STM images were subjected to a Fourier filter to remove atomic-scale features and thereby highlight the row structures and distortions caused by creep.

[0045] As shown in Figure 6, the conventional scanner (curve in Figure 6) continues to move (creep) despite the constant control signal, resulting in severe warping of the scanned image of Figure 5B obtained after repositioning of the probe, and an undesirable shift of the scanned area as the scan progresses. Figure 6 demonstrates that over 100 seconds pass before the creep rate of the conventional scanner becomes negligible. In contrast, the scanner of the present disclosure (lower line in Figure 6) immediately locks into its new position, moves as commanded, and does not creep, allowing an image to be recorded immediately after repositioning of the probe, instantly giving an accurate usable scan as shown in Figure 5D.

[0046] All references and patent documents cited herein are incorporated by reference to the same extent as if each reference was individually and specifically incorporated by reference.

[0047] As will be appreciated from the foregoing detailed description and the figures and claims, those skilled in the art can make modifications and variations to the preferred embodiments of the invention without departing from the scope of the invention as defined in the following claims.

[0048] References JPEG0007629907000001.jpg214166JPEG0007629907000002.jpg166166

[0049] [Explanation of symbols] 10 Nanopositioning System 12 Actuator 14 Lithium niobate shear piezoelectric crystal 16 Metal Plate 18 Stationary Stage 20 electrodes 22 Ceramic ball 24 V groove 26 Flat Plate 28 Moving Stage 28' Moving Stage 30 Disc Magnets 100 Silicon

Claims

1. 1. A nanopositioning system for fine and coarse nanopositioning comprising at least one actuator, the at least one actuator comprising a high Curie temperature material, the nanopositioning system configured to apply a voltage to the at least one actuator to cause coarse movement by the at least one actuator.

2. The nanopositioning system of claim 1, further configured to apply a voltage to the at least one actuator to cause fine movement by the at least one actuator.

3. The nanopositioning system of claim 2, wherein the at least one actuator is a shear actuator, a longitudinal actuator, or a bimorph actuator.

4. A nanopositioning system as described in claim 1, further comprising at least one second actuator, the at least one second actuator comprising a high Curie temperature material, the nanopositioning system being further configured to apply a voltage to the at least one second actuator to cause micromovement by the at least one second actuator.

5. The nanopositioning system of claim 4, further configured to apply a voltage to the at least one second actuator to produce coarse movement by the at least one second actuator.

6. The nanopositioning system of claim 5, wherein the at least one second actuator is a bimorph actuator, a longitudinal actuator, or a shear actuator.

7. The nanopositioning system of claim 4, wherein the at least one actuator is a bimorph actuator or a shear actuator, and the at least one second actuator is a component of a shear actuator or a crawler.

8. A nanopositioning system as described in any one of claims 1 to 3, further comprising a probe, wherein the at least one actuator is configured to controllably position the probe.

9. A nanopositioning system as described in any one of claims 4 to 7, further comprising a probe, wherein the at least one actuator and the at least one second actuator are configured to controllably position the probe.

10. The nanopositioning system of claim 1 , wherein the high Curie temperature material is a high Curie temperature ferroelectric material.

11. 10. The nanopositioning system of claim 1, wherein the high Curie temperature material provides motion that is substantially consistent and substantially hysteresis and creep free as a function of frequency and amplitude of applied voltage.

12. The nanopositioning system of claim 1 , wherein the high Curie temperature material provides Z motion that is separated from the XY motion.

13. 1. A nanopositioning method comprising: (a) positioning a probe relative to a first area of ​​a substrate using coarse motion; (b) using fine motion to read, write, or scan a first area of ​​the substrate less than 60 seconds after positioning the probe; Including, nanopositioning is substantially creepless; The positioning of the probe in step (a) is actuated by a high Curie temperature material activated by an applied voltage; method.

14. The method of claim 13 , wherein the probe is a scanning probe microscope probe.

15. The method of claim 14 , further comprising recording a scanning probe microscopy (SPM) image of the first area of ​​the substrate.

16. The method of claim 13 , wherein the SPM image is substantially free of distortion.

17. The method of claim 13, wherein the probe is positioned using a fine scanner repositioning technique.

18. The method of claim 13 , wherein the coarse stepping is performed using a coarse motor of a scanning probe microscope.

19. 14. The method of claim 13, further comprising communicating data obtained by reading, writing, or scanning the first area of ​​the substrate to a processor configured to interpret the data.

20. 20. The method of any one of claims 13 to 19, wherein the substrate is a hydrogen-terminated Si(100) surface.

21. 20. The method of any one of claims 13 to 19, wherein the movement of the probe is actuated by a high Curie temperature piezoelectric bimorph activated by an applied voltage.

22. A nanopositioning system configured to perform the method of any one of claims 13 to 19.

23. 20. An attachment to an existing scanning probe microscope, said attachment enabling said existing scanning probe microscope to carry out the method according to any one of claims 13 to 19.

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