CN110907663A - Kelvin probe force microscope measuring method based on T-shaped cantilever beam probe - Google Patents

Kelvin probe force microscope measuring method based on T-shaped cantilever beam probe Download PDF

Info

Publication number
CN110907663A
CN110907663A CN201911313094.7A CN201911313094A CN110907663A CN 110907663 A CN110907663 A CN 110907663A CN 201911313094 A CN201911313094 A CN 201911313094A CN 110907663 A CN110907663 A CN 110907663A
Authority
CN
China
Prior art keywords
probe
shaped cantilever
cantilever beam
sample
beam probe
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.)
Granted
Application number
CN201911313094.7A
Other languages
Chinese (zh)
Other versions
CN110907663B (en
Inventor
谢晖
张号
宋健民
孟祥和
耿俊媛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Harbin Institute of Technology
Original Assignee
Harbin Institute of Technology
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Harbin Institute of Technology filed Critical Harbin Institute of Technology
Priority to CN201911313094.7A priority Critical patent/CN110907663B/en
Publication of CN110907663A publication Critical patent/CN110907663A/en
Application granted granted Critical
Publication of CN110907663B publication Critical patent/CN110907663B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
    • G01Q60/00—Particular types of SPM [Scanning Probe Microscopy] or microscopes; Essential components thereof
    • G01Q60/24—AFM [Atomic Force Microscopy] or apparatus therefor, e.g. AFM probes
    • G01Q60/26—Friction force microscopy
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01Q—SCANNING-PROBE TECHNIQUES OR APPARATUS; APPLICATIONS OF SCANNING-PROBE TECHNIQUES, e.g. SCANNING PROBE MICROSCOPY [SPM]
    • G01Q60/00—Particular types of SPM [Scanning Probe Microscopy] or microscopes; Essential components thereof
    • G01Q60/24—AFM [Atomic Force Microscopy] or apparatus therefor, e.g. AFM probes
    • G01Q60/38—Probes, their manufacture, or their related instrumentation, e.g. holders

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

A Kelvin probe force microscope measurement method based on a T-shaped cantilever beam probe belongs to the technical field of atomic force microscope measurement. The invention aims at the problem that the accuracy of a surface potential measurement result is influenced by a serious cantilever homogenization effect in the existing AM-KPFM measurement. The method comprises the steps of carrying out mechanical excitation on a T-shaped cantilever probe under a first-order bending resonance frequency to enable the T-shaped cantilever probe to vibrate under a preset normal amplitude; approaching a sample to be detected, and attenuating the normal amplitude of the T-shaped cantilever beam probe to a normal amplitude set value; applying alternating current voltage and direct current compensation voltage with the frequency of the first-order torsional resonance frequency of the T-shaped cantilever beam probe between the T-shaped cantilever beam probe and a sample to be detected; obtaining a relation curve of the direct current compensation voltage and the torsional amplitude of the T-shaped cantilever beam probe; further determining a set value of the torsional amplitude; based on the method, the sample to be tested is measured according to the set scanning step distance and the number of scanning test points. The method is used for realizing the measurement of the surface appearance and the local surface potential of the sample.

Description

Kelvin probe force microscope measuring method based on T-shaped cantilever beam probe
Technical Field
The invention relates to a Kelvin probe force microscope measuring method based on a T-shaped cantilever beam probe, belonging to the technical field of atomic force microscope measurement.
Background
Kelvin Probe Force Microscopy (KPFM), a member of the SPM family, combines Kelvin technology with Atomic Force Microscopy (AFM) to characterize sample surface potentials and surface topographies. According to different detection modes, the KPFM can be divided into two working modes: amplitude Modulation (AM) mode and Frequency Modulation (FM) mode, in which AM-KPFM and FM-KPFM are detected based on electrostatic force and electrostatic force gradient, respectively. Although the existing AM-KPFM mode based on the normal signal of the rectangular beam probe can realize the measurement of the surface potential of the sample, in the AM-KPFM measurement based on the normal signal of the rectangular beam probe, the electrostatic force interaction between the cantilever of the rectangular beam probe and the sample greatly contributes to the whole feedback signal, so that the effective sample in the measurement is not limited under the needle tip, and the sample under the cantilever of the probe brings serious homogenization effect to the surface potential measurement result, thereby obviously influencing the accuracy of the surface potential measurement result.
Disclosure of Invention
The invention provides a Kelvin probe force microscope measuring method based on a T-shaped cantilever beam probe, aiming at the problems that the AM-KPFM measurement of normal signals of the existing rectangular beam probe has serious cantilever homogenization effect and influences the accuracy of surface potential measurement results.
The invention relates to a Kelvin probe force microscope measuring method based on a T-shaped cantilever beam probe, which comprises the following steps of:
carrying out mechanical excitation on the T-shaped cantilever beam probe under the first-order bending resonance frequency to enable the T-shaped cantilever beam probe to vibrate under a preset normal amplitude; gradually approaching the sample to be detected until the normal amplitude of the T-shaped cantilever beam probe is attenuated to a normal amplitude set value;
then applying alternating current voltage and direct current compensation voltage with the frequency of the first-order torsional resonance frequency of the T-shaped cantilever beam probe between the T-shaped cantilever beam probe and a sample to be detected; changing the magnitude of the direct current compensation voltage to obtain a relation curve of the direct current compensation voltage and the torsional amplitude of the T-shaped cantilever beam probe;
selecting a torsion amplitude set value of the T-shaped cantilever beam probe according to the relation curve; adjusting the direct current compensation voltage through a Kelvin controller to enable the torsional amplitude of the T-shaped cantilever beam probe to be equal to a set torsional amplitude value;
setting a scanning step pitch and a scanning test point number of a sample to be tested, wherein the scanning step pitch and the scanning test point number comprise an X direction and a Y direction; keeping the position of the T-shaped cantilever beam probe unchanged, sequentially changing scanning test points of the T-shaped cantilever beam probe, and keeping the normal amplitude and the torsional amplitude of the T-shaped cantilever beam probe equal to a normal amplitude set value and a torsional amplitude set value at each scanning test point; and realizing the measurement of the sample to be measured.
According to the Kelvin probe force microscope measuring method based on the T-shaped cantilever beam probe, the measurement of the sample to be measured is realized by the following steps:
fixing a sample to be detected on a Kelvin scanning sample table, and changing the coordinate position of the sample to be detected through the Kelvin scanning sample table; keeping the Z-direction coordinate of the T-shaped cantilever beam probe unchanged at each scanning test point, and enabling the normal amplitude of the T-shaped cantilever beam probe to be equal to the normal amplitude set value by changing the Z-direction coordinate of the sample to be tested; and sequentially recording Z-direction coordinates of the Kelvin scanning sample stage when each scanning test point is used for realizing the measurement of the surface topography of the sample to be measured.
According to the Kelvin probe force microscope measuring method based on the T-shaped cantilever beam probe, the measurement of the sample to be measured is realized by the following steps:
obtaining the local surface potential difference U between the T-shaped cantilever beam probe and the scanning test point of the sample to be testedCPD：
The total potential difference delta U between the T-shaped cantilever beam probe and the sample to be detected is as follows:
ΔU＝UDC-UCPD+UTsin(ωt)，
in the formula of UDCFor said DC compensation voltage, UTsin (ω T) is the alternating voltage, ω is a T-shaped cantilever probeA first order torsional resonance frequency of the needle;
at the moment, the electrostatic acting force F between the T-shaped cantilever probe and the sample to be measuredelComprises the following steps:
Figure BDA0002325054900000021
wherein C is the capacitance between the T-shaped cantilever beam probe and the sample to be detected, and z is the distance between the T-shaped cantilever beam probe and the sample to be detected; recording the direct current compensation voltage when the torsional amplitude of the T-shaped cantilever beam probe is equal to the set value of the torsional amplitude, and determining the local surface potential difference U by combining the relation curve of the direct current compensation voltage and the torsional amplitude of the T-shaped cantilever beam probeCPD。
According to the Kelvin probe force microscope measuring method based on the T-shaped cantilever beam probe, the T-shaped cantilever beam probe comprises a longitudinal beam, a cross beam, a needle point and a probe holder, the probe holder is connected to a probe seat of the Kelvin probe force microscope, the fixed end of the longitudinal beam is connected to the probe holder, the cross beam is connected with the free end of the longitudinal beam in a T shape, and the needle point is arranged on the lower surface of the cross beam.
According to the Kelvin probe force microscope measuring method based on the T-shaped cantilever beam probe, a test area of a sample to be tested is placed in the center of a view field of a microscope by controlling a Kelvin scanning sample stage; placing the needle point of the T-shaped cantilever beam probe above the test area, and adjusting the laser spot of the T-shaped cantilever beam probe to be positioned in the center of the front end of the longitudinal beam;
performing frequency sweeping operation on the T-shaped cantilever beam probe through a frequency sweeping vibration exciter to obtain a first-order bending resonance frequency and a first-order torsion resonance frequency of the T-shaped cantilever beam probe;
the method comprises the steps that the T-shaped cantilever beam probe is mechanically excited under the first-order bending resonance frequency through piezoelectric ceramics, a laser force measuring system is used for detecting resonance signals generated by the T-shaped cantilever beam probe, and the normal amplitude of the T-shaped cantilever beam probe is obtained through a phase-locked amplifier, so that a sample to be detected is close to the T-shaped cantilever beam probe in the Z-axis direction until the normal amplitude of the T-shaped cantilever beam probe is equal to a set normal amplitude value;
then, under the current relative position relationship between the sample to be detected and the T-shaped cantilever beam probe, applying alternating current voltage and direct current compensation voltage under first-order torsional resonance frequency between the sample to be detected and the T-shaped cantilever beam probe, obtaining the torsional amplitude of the T-shaped cantilever beam probe through another phase-locked amplifier, then obtaining a relationship curve of the direct current compensation voltage and the torsional amplitude, and selecting a torsional amplitude set value for the Kelvin controller based on the relationship curve;
the torsional amplitude output by the other phase-locked amplifier is used as a feedback signal, the Kelvin controller controls the direct-current power supply to output direct-current compensation voltage to act between the sample to be detected and the T-shaped cantilever beam probe, so that the torsional amplitude output by the other phase-locked amplifier is equal to a set value of the torsional amplitude, and the local surface potential difference U between the sample to be detected and the T-shaped cantilever beam probe is realizedCPDCompensation of (2);
obtaining the local surface potential difference U between the sample to be detected and the T-shaped cantilever beam probe according to the relation curve of the DC compensation voltage and the torsional amplitude of the T-shaped cantilever beam probeCPD；
Recording the coordinates of a Kelvin scanning sample stage where a sample to be tested is located and the local surface potential difference U in the process of testing the scanning test points one by oneCPDAnd the measurement of the sample to be measured is realized.
The invention has the beneficial effects that: the method is realized based on the existing Kelvin probe force microscope measuring system, and the rectangular beam probe in the prior art is replaced by a T-shaped cantilever beam probe, so that the surface appearance and the local surface potential of the sample are represented. The surface appearance of a sample is measured through a normal signal of the T-shaped cantilever beam probe, and the measurement of the local surface potential of the sample under the weak homogenization effect is realized through a torsion signal of the T-shaped cantilever beam probe.
The method breaks through the serious homogenization effect brought by the cantilever when the surface potential is measured by using the normal signal of the rectangular beam probe as feedback in the traditional KPFM, and realizes the measurement of the local surface potential of the sample under the condition of weak homogenization effect through the torsion signal of the T-shaped cantilever beam probe; the Kelvin probe force microscope measurement method based on the T-shaped cantilever beam probe provides a technical basis for further researching the application of the T-shaped cantilever beam probe in the field of surface potential measurement. Compared with the traditional KPFM, the method can effectively inhibit the homogenization effect brought by the cantilever of the probe in the surface potential measurement by taking the torsion signal of the T-shaped cantilever probe as feedback, does not need to change a KPFM test system or a Kelvin controller, is compatible with the traditional KPFM test system, and has high practical value in the field of KPFM test methods and system research.
Drawings
FIG. 1 is an exemplary flow chart of a Kelvin probe force microscopy measurement method based on a T-shaped cantilever probe according to the present invention;
FIG. 2 is a schematic structural view of the T-shaped cantilever probe;
FIG. 3 is a schematic diagram of the overall structure of a Kelvin probe force microscope for carrying out the method of the invention;
FIG. 4 is a schematic diagram of the structure of a probe hand of a Kelvin probe force microscope;
FIG. 5 is a side view of a Kelvin scanning sample stage of a Kelvin probe force microscope;
FIG. 6 is a top view of a Kelvin scanning sample stage of a Kelvin probe force microscope;
FIG. 7 is a functional block diagram of a method of implementing the present invention;
FIG. 8 is a surface topography map obtained by scanning a sample to be tested using the method of the present invention;
FIG. 9 is a cross-sectional view corresponding to the reference line in FIG. 8;
FIG. 10 is a graph of the surface potential difference obtained by scanning a sample to be measured using the method of the present invention;
FIG. 11 is a graph of statistical distributions and bimodal fit results corresponding to the data in FIG. 10.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.
The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.
In a first embodiment, as shown in fig. 1 to 7, the invention provides a kelvin probe force microscope measurement method based on a T-shaped cantilever probe, which includes the following steps:
carrying out mechanical excitation on the T-shaped cantilever beam probe under the first-order bending resonance frequency to enable the T-shaped cantilever beam probe to vibrate under a preset normal amplitude; gradually approaching the sample to be detected until the normal amplitude of the T-shaped cantilever beam probe is attenuated to a normal amplitude set value;
then applying alternating current voltage and direct current compensation voltage with the frequency of the first-order torsional resonance frequency of the T-shaped cantilever beam probe between the T-shaped cantilever beam probe and a sample to be detected; changing the magnitude of the direct current compensation voltage to obtain a relation curve of the direct current compensation voltage and the torsional amplitude of the T-shaped cantilever beam probe;
selecting a torsion amplitude set value of the T-shaped cantilever beam probe according to the relation curve; adjusting the direct current compensation voltage through a Kelvin controller to enable the torsional amplitude of the T-shaped cantilever beam probe to be equal to a set torsional amplitude value;
setting a scanning step pitch and a scanning test point number of a sample to be tested, wherein the scanning step pitch and the scanning test point number comprise an X direction and a Y direction; keeping the position of the T-shaped cantilever beam probe unchanged, sequentially changing scanning test points of the T-shaped cantilever beam probe, and keeping the normal amplitude and the torsional amplitude of the T-shaped cantilever beam probe equal to a normal amplitude set value and a torsional amplitude set value at each scanning test point; and realizing the measurement of the sample to be measured.
The surface potential energy accurately reflects the surface structure characteristics of the material and the physical and chemical changes thereof, and is one of important parameters in the processes of catalyst activity, doping and band bending of semiconductors, charge capture in dielectrics and corrosion. The local surface potential is very important for understanding the performance of the material in micro-nano scale, the microbial activity and the function of a microelectronic device, so that the accurate measurement of the local surface potential of the sample is very meaningful. In the embodiment, the torsion signal of the T-shaped cantilever beam probe is used as feedback to realize the measurement of the local surface potential of the sample, and the normal signal of the T-shaped cantilever beam probe is used to realize the measurement of the surface appearance of the sample.
The Kelvin controller can be arranged in an upper computer shown in fig. 7, parameters of the Kelvin controller are set and then started, and the direct-current compensation voltage U is adjustedDCMaking the torsional amplitude of the probe equal to a set value; after the next test point of the sample to be tested is changed, the sample stage and the U are scanned by adjusting KelvinDCTo keep the normal and torsional amplitudes of the probe equal to their set values; the above processes are repeated, and the imaging measurement of the sample to be measured can be realized.
Further, as shown in fig. 3, the implementing of the measurement on the sample to be measured includes:
fixing a sample to be detected on a Kelvin scanning sample table, and changing the coordinate position of the sample to be detected through the Kelvin scanning sample table; keeping the Z-direction coordinate of the T-shaped cantilever beam probe unchanged at each scanning test point, and enabling the normal amplitude of the T-shaped cantilever beam probe to be equal to the normal amplitude set value by changing the Z-direction coordinate of the sample to be tested; and sequentially recording Z-direction coordinates of the Kelvin scanning sample stage when each scanning test point is used for realizing the measurement of the surface topography of the sample to be measured.
In this embodiment, the distance between the T-shaped cantilever probe and the sample to be measured is kept constant, and the normal amplitude of the T-shaped cantilever probe can be always equal to the set normal amplitude value. Because the surface to be tested of the sample to be tested has undulation, if the distance between the T-shaped cantilever beam probe and the sample to be tested is kept unchanged, under the condition that the Z-direction coordinate of the T-shaped cantilever beam probe is unchanged, the Z-direction height of the position of the sample stage can be changed by Kelvin scanning to drive the coordinate position of the sample to be tested to be changed, so that when the current test point of the surface to be tested of the sample to be tested is a bulge, the sample to be tested moves downwards to keep the distance between the sample to be tested and the T-shaped cantilever beam probe unchanged; and when the current test point of the surface to be tested of the sample to be tested is a pit, moving the sample to be tested upwards to keep the distance between the sample to be tested and the T-shaped cantilever beam probe unchanged. And finally, recording Z-direction coordinates of the Kelvin scanning sample stage to obtain a surface topography image of the sample to be detected.
Still further, the measurement of the sample to be measured further includes:
obtaining the local surface potential difference U between the T-shaped cantilever beam probe and the scanning test point of the sample to be testedCPD：
The total potential difference delta U between the T-shaped cantilever beam probe and the sample to be detected is as follows:
ΔU＝UDC-UCPD+UTsin(ωt)，
in the formula of UDCFor said DC compensation voltage, UTsin (ω T) is the alternating voltage, ω is the first order torsional resonance frequency of the T-shaped cantilever probe;
at the moment, the electrostatic acting force F between the T-shaped cantilever probe and the sample to be measuredelComprises the following steps:
Figure BDA0002325054900000061
wherein C is the capacitance between the T-shaped cantilever beam probe and the sample to be detected, and z is the distance between the T-shaped cantilever beam probe and the sample to be detected; recording the direct current compensation voltage when the torsional amplitude of the T-shaped cantilever beam probe is equal to the set value of the torsional amplitude, and determining the local surface potential difference U by combining the relation curve of the direct current compensation voltage and the torsional amplitude of the T-shaped cantilever beam probeCPD。
During the test, the local surface potential difference between the probe and the sample is measured by using the torsion signal of the probe as feedback. From the above formula, when U isDC＝UCPDTime, electrostatic force FelThe effect on the probe at the frequency (ω) at which the phase and amplitude information of the probe feedback signal is obtained using a lock-in amplifier is eliminated. The amplitude signal output by the phase-locked amplifier is used as feedback to be input to an upper computer-Kelvin controller which adjusts UDCTwisting the probeThe amplitude is equal to the set value. When the amplitude of the output of the phase-locked amplifier is equal to the set value of the torsional amplitude of the probe, the U of the test point is recordedDCAnd combined with UDCThe corresponding local surface potential difference (U) between the probe and the sample can be obtained according to the relation curve of the probe torsion amplitude signalCPD)。
Further, as shown in fig. 2, the T-shaped cantilever probe includes a longitudinal beam 7-4-1, a cross beam 7-4-2, a needle tip 7-4-3, and a probe holder 7-4-4, the probe holder 7-4-4 is connected to a probe base of the kelvin probe force microscope, a fixed end of the longitudinal beam 7-4-1 is connected to the probe holder 7-4-4, the cross beam 7-4-2 is connected to a free end of the longitudinal beam 7-4-1 in a T-shape, and the needle tip 7-4-3 is disposed on a lower surface of the cross beam 7-4-2.
The method is realized based on a Kelvin probe force microscope measuring system, and the Kelvin probe force microscope measuring system mainly comprises a multi-frequency-state driving AFM system, a Kelvin sample stage, a probe hand and an upper computer. The test procedure of the present invention involves the driving of the probe at two frequencies, including: 1) mechanical drive at the first order bending resonance frequency of the T-shaped cantilever probe, 2) electrical excitation at the first order torsional resonance frequency between the T-shaped cantilever probe and the sample. And the upper computer respectively realizes displacement control and potential compensation of the positioning table by taking the normal signal and the torsion signal of the T-shaped cantilever beam probe as feedback, so that the surface appearance and the local surface potential of the sample are measured.
As shown in fig. 3, the kelvin probe force microscope measurement system of the present invention includes a frame 1, a two-dimensional adjustment micro platform 2 of a four-quadrant position detector, a one-dimensional adjustment micro platform I3, a four-quadrant position detector 4, a reflective laser convex lens 5, a laser mirror 6, a probe hand 7, an XYZ micrometer positioning stage 8, a probe hand support 9, a one-dimensional wide-range adjustment micro platform 10, a table top 11, an XY micrometer positioning stage 12, an XYZ nanometer positioning stage 13, a sample stage support 14, a kelvin scanning sample stage 15, an incident laser focusing convex lens 16, a one-dimensional adjustment micro platform II17, a semiconductor laser generator 18, a laser generator angle adjustment mechanism 19, and an optical microscope 20.
The Kelvin probe force microscope based on the T-shaped cantilever beam probe comprises a table top 11, wherein a rack 1, a one-dimensional large-range adjusting micro-platform 10, an XY micrometer positioning platform 12 and an optical microscope 20 are mounted on the table top 11. The Kelvin scanning sample stage 15 is mounted on the XY micrometer positioning stage 12 through a sample stage support 14 and an XYZ nanometer positioning stage 13, the laser force measuring system is mounted on the machine frame 1, and the probe hand 7 is mounted on the one-dimensional wide-range adjusting micro-platform 10 through a probe hand support 9 and the XYZ micrometer positioning stage 8.
The laser force measuring system is respectively composed of a laser generator angle adjusting mechanism 19, a semiconductor laser generator 18, an incident laser focusing convex lens 16, a laser reflector 6, a reflecting laser convex lens 5, a four-quadrant position detector 4, a one-dimensional adjusting micro platform II17, a one-dimensional adjusting micro platform I3 and a four-quadrant position detector two-dimensional adjusting micro platform 2.
Referring to fig. 4, the probe hand 7 is composed of a probe hand base 7-1, piezoelectric ceramics 7-2, a probe base 7-3, a T-shaped cantilever probe 7-4, a shielding plate 7-5, a T-shaped cantilever probe fixing plate 7-6 and a connecting terminal 7-7. Insulation sheets are arranged between the probe hand base 7-1 and the piezoelectric ceramic 7-2, between the piezoelectric ceramic 7-2 and the probe base 7-3 and between the shielding sheet 7-5 and the T-shaped cantilever beam probe fixing plate 7-6, the probe hand base 7-1, the piezoelectric ceramic 7-2, the shielding sheet 7-5 and the T-shaped cantilever beam probe fixing plate 7-6 are electrically connected with the corresponding interfaces of the wiring terminals 7-7, and the T-shaped cantilever beam probe fixing plate 7-6 is electrically connected with the T-shaped cantilever beam probe 7-4. The terminals 7-7 are electrically connected to corresponding electrical devices. The force deflection of the probe is measured by a laser force measurement subsystem.
Referring to fig. 5 and 6, the kelvin scanning sample stage 15 is composed of a kelvin sample stage base 15-1, a sample holder 15-2, a connecting wire 15-3, a set screw 15-4, a wire harness block 15-5, a copper pressing sheet 15-6, a sample 15-7 and an insulation fixing screw 15-8. Wherein, insulation sheets are respectively arranged between the Kelvin sample stage base 15-1 and the sample seat 15-2, and between the sample seat 15-2 and the sample 15-7 (sample to be detected), and the sample 15-7 and the copper pressing sheet 15-6, the copper pressing sheet 15-6 and the connecting line 15-3 are electrically connected. The connection line 15-3 is electrically connected to the corresponding electrical device.
The T-shaped cantilever probe 7-4 in the embodiment can generate two feedback signals of normal and torsion in the test. The method breaks through the traditional mode of using a normal signal of a rectangular beam probe as a feedback signal in AM-KPFM surface potential measurement, uses a torsion signal of a T-shaped cantilever beam probe as the feedback signal in AM-KPFM surface potential measurement, fully utilizes the structural symmetry of the T-shaped cantilever beam probe, uses the torsion signal as the feedback signal in surface potential measurement, and can effectively inhibit the homogenization effect of a cantilever in an AM mode.
Still further, as shown in fig. 1 to 7, the test area of the sample to be tested is placed in the center of the field of view of the microscope by controlling the kelvin scanning sample stage; placing a needle tip 7-4-3 of the T-shaped cantilever beam probe above the test area, and adjusting a laser spot of the T-shaped cantilever beam probe to be positioned in the center of the front end of the longitudinal beam 7-4-1;
performing frequency sweeping operation on the T-shaped cantilever beam probe through a frequency sweeping vibration exciter to obtain a first-order bending resonance frequency and a first-order torsion resonance frequency of the T-shaped cantilever beam probe;
the method comprises the steps that the T-shaped cantilever beam probe is mechanically excited under the first-order bending resonance frequency through piezoelectric ceramics, a laser force measuring system is used for detecting resonance signals generated by the T-shaped cantilever beam probe, and the normal amplitude of the T-shaped cantilever beam probe is obtained through a phase-locked amplifier, so that a sample to be detected is close to the T-shaped cantilever beam probe in the Z-axis direction until the normal amplitude of the T-shaped cantilever beam probe is equal to a set normal amplitude value;
then, under the current relative position relationship between the sample to be detected and the T-shaped cantilever beam probe, applying alternating current voltage and direct current compensation voltage under first-order torsional resonance frequency between the sample to be detected and the T-shaped cantilever beam probe, obtaining the torsional amplitude of the T-shaped cantilever beam probe through another phase-locked amplifier, then obtaining a relationship curve of the direct current compensation voltage and the torsional amplitude, and selecting a torsional amplitude set value for the Kelvin controller based on the relationship curve;
the torsional amplitude output by the other phase-locked amplifier is used as a feedback signal, the Kelvin controller controls the direct-current power supply to output direct-current compensation voltage to act between the sample to be tested and the T-shaped cantilever beam probe, so that the torsional amplitude output by the other phase-locked amplifier is equal to a set value of the torsional amplitude,so as to realize the local surface potential difference U between the sample to be detected and the T-shaped cantilever beam probeCPDCompensation of (2);
obtaining the local surface potential difference U between the sample to be detected and the T-shaped cantilever beam probe according to the relation curve of the DC compensation voltage and the torsional amplitude of the T-shaped cantilever beam probeCPD；
Recording the coordinates of a Kelvin scanning sample stage where a sample to be tested is located and the local surface potential difference U in the process of testing the scanning test points one by oneCPDAnd the measurement of the sample to be measured is realized.
The specific cooperation of the present embodiment with a kelvin probe force microscope measurement system based on a T-shaped cantilever probe comprises:
1) initializing a system, fixing a prepared sample 15-7 on a sample seat 15-2, installing a T-shaped cantilever beam probe 7-4 on a probe hand 7, then respectively installing a Kelvin scanning sample table 15 and the probe hand 7 on a sample table support 14 and a probe hand support 9, and finally electrically connecting a wiring terminal with corresponding equipment;
2) moving the XY-micrometer positioning stage 12, preliminarily positioning the sample 15-7 through the optical microscope 20, selecting a suitable measurement region, and moving the region to the center of the field of view of the optical microscope 20;
3) moving a one-dimensional large-range adjustment micro platform 10 and an XYZ micrometer positioning table 8, roughly aligning the T-shaped cantilever beam probe 7-4, placing the probe tip above the proper measurement area selected in the step 2, and adjusting the laser spot of the T-shaped cantilever beam probe 7-4 to be in the center of the front end of the probe longitudinal beam;
4) performing frequency sweeping operation on the T-shaped cantilever beam probe 7-4 through a frequency sweeping vibration exciter to obtain a first-order bending resonance frequency and a first-order torsion resonance frequency of the T-shaped cantilever beam probe 7-4;
5) roughly adjusting the distance between the T-shaped cantilever beam probe 7-4 and the sample 15-7, readjusting the laser spot of the T-shaped cantilever beam probe 7-4 to the center of the front end of the probe longitudinal beam, and preparing to start an upper computer-position servo control;
6) mechanically exciting the probe under the first-order bending resonance frequency of the probe through piezoelectric ceramics 7-2, detecting a resonance signal generated by a T-shaped cantilever beam probe 7-4 by using a laser force measuring system, obtaining the normal amplitude of the probe through a phase-locked amplifier 1 in the figure 7, starting position servo control, controlling an XYZ nano positioning table 13 to rapidly approach the T-shaped cantilever beam probe 7-4 in the Z-axis direction, and enabling the normal amplitude of the T-shaped cantilever beam probe 7-4 to be equal to a set value;
7) applying electric excitation at first-order torsional resonance frequency between the T-shaped cantilever beam probe 7-4 and the sample 15-7, obtaining the torsional amplitude of the probe at the frequency through the phase-locked amplifier 2, and then obtaining UDCA relation curve with the probe torsional amplitude, and a set value of the probe torsional amplitude is selected for the Kelvin controller;
8) the Kelvin controller is turned on, the amplitude output by the phase-locked amplifier 2 is used as a feedback signal by the program, and the direct-current power supply is controlled to output a direct-current compensation voltage UDCActs between the T-shaped cantilever probe 7-4 and the sample 15-7 to compensate for the local potential difference U between the T-shaped cantilever probe 7-4 and the surface of the sample 15-7CPDTo ensure that the amplitude output by the lock-in amplifier 2 is equal to the set value of the probe torsional amplitude signal;
9) through the steps, the DC compensation voltage U can be output by the DC power supplyDCAnd the relation curve of the local potential difference and the probe torsional amplitude are obtained, and the local potential difference U of the T-shaped cantilever beam probe 7-4 and the sample 15-7 is obtainedCPD；
10) The scanning step distance and the number of scanning points are set, and then image scanning is started.
The specific embodiment is as follows: the method is used for measuring the tobacco mosaic virus sample with the nanometer diameter; FIG. 8 is a scanned surface topography of a tobacco mosaic virus sample, wherein the linear portions of the protrusions are tobacco mosaic virus; FIG. 9 is a cross-sectional view corresponding to the reference line in FIG. 8, showing a height of 20 nm; FIG. 10 is a graph of potential differences across a scanning surface for a tobacco mosaic virus sample; FIG. 11 is a graph of the statistical distribution and the results of a bimodal fit corresponding to the data in FIG. 10, showing that the difference in potential between the tobacco mosaic virus sample and the substrate was 94.1mV, with a sweep range of 0.75 μm by 0.75 μm and a sweep point number of 150 by 150.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.

Claims (5)

1. A Kelvin probe force microscope measurement method based on a T-shaped cantilever probe is characterized by comprising the following steps:
carrying out mechanical excitation on the T-shaped cantilever beam probe under the first-order bending resonance frequency to enable the T-shaped cantilever beam probe to vibrate under a preset normal amplitude; gradually approaching the sample to be detected until the normal amplitude of the T-shaped cantilever beam probe is attenuated to a normal amplitude set value;
then applying alternating current voltage and direct current compensation voltage with the frequency of the first-order torsional resonance frequency of the T-shaped cantilever beam probe between the T-shaped cantilever beam probe and a sample to be detected; changing the magnitude of the direct current compensation voltage to obtain a relation curve of the direct current compensation voltage and the torsional amplitude of the T-shaped cantilever beam probe;
selecting a torsion amplitude set value of the T-shaped cantilever beam probe according to the relation curve; adjusting the direct current compensation voltage through a Kelvin controller to enable the torsional amplitude of the T-shaped cantilever beam probe to be equal to a set torsional amplitude value;
setting a scanning step pitch and a scanning test point number of a sample to be tested, wherein the scanning step pitch and the scanning test point number comprise an X direction and a Y direction; keeping the position of the T-shaped cantilever beam probe unchanged, sequentially changing scanning test points of the T-shaped cantilever beam probe, and keeping the normal amplitude and the torsional amplitude of the T-shaped cantilever beam probe equal to a normal amplitude set value and a torsional amplitude set value at each scanning test point; and realizing the measurement of the sample to be measured.
2. The Kelvin probe force microscopy measurement method based on a T-shaped cantilever probe according to claim 1, characterized in that the enabling of the measurement of the sample to be measured comprises:
fixing a sample to be tested on a Kelvin scanning sample stage, changing the coordinate position of the sample to be tested through the Kelvin scanning sample stage, and realizing the transformation of a scanning test point; keeping the Z-direction coordinate of the T-shaped cantilever beam probe unchanged at each scanning test point, and enabling the normal amplitude of the T-shaped cantilever beam probe to be equal to the normal amplitude set value by changing the Z-direction coordinate of the sample to be tested; and sequentially recording Z-direction coordinates of the Kelvin scanning sample stage when each scanning test point is used for realizing the measurement of the surface topography of the sample to be measured.
3. The Kelvin probe force microscopy measurement method based on a T-shaped cantilever probe according to claim 1 or 2, characterized in that the implementation of the measurement of the sample to be measured further comprises:
obtaining the local surface potential difference U between the T-shaped cantilever beam probe and the scanning test point of the sample to be testedCPD：
The total potential difference delta U between the T-shaped cantilever beam probe and the sample to be detected is as follows:
ΔU＝UDC-UCPD+UTsin(ωt)，
in the formula of UDCFor said DC compensation voltage, UTsin (ω T) is the alternating voltage, ω is the first order torsional resonance frequency of the T-shaped cantilever probe;
at the moment, the electrostatic acting force F between the T-shaped cantilever probe and the sample to be measuredelComprises the following steps:
Figure FDA0002325054890000011
wherein C is the capacitance between the T-shaped cantilever beam probe and the sample to be detected, and z is the distance between the T-shaped cantilever beam probe and the sample to be detected; recording the direct current compensation voltage when the torsional amplitude of the T-shaped cantilever beam probe is equal to the set value of the torsional amplitude, and determining the local surface potential difference U by combining the relation curve of the direct current compensation voltage and the torsional amplitude of the T-shaped cantilever beam probeCPD。
4. The Kelvin probe force microscope measurement method based on the T-shaped cantilever beam probe according to claim 3, characterized in that the T-shaped cantilever beam probe comprises a longitudinal beam (7-4-1), a transverse beam (7-4-2), a needle tip (7-4-3) and a probe holder (7-4-4), the probe holder (7-4-4) is connected to a probe seat of the Kelvin probe force microscope, the fixed end of the longitudinal beam (7-4-1) is connected to the probe holder (7-4-4), the transverse beam (7-4-2) is connected with the free end of the longitudinal beam (7-4-1) in a T shape, and the needle tip (7-4-3) is arranged on the lower surface of the transverse beam (7-4-2).
5. The T-shaped cantilever probe-based Kelvin probe force microscopy measurement method according to claim 4, wherein the test area of the sample to be tested is placed in the center of the microscope's field of view by controlling the Kelvin scanning sample stage; placing a needle point (7-4-3) of the T-shaped cantilever beam probe above the test area, and adjusting a laser spot of the T-shaped cantilever beam probe to be positioned at the center of the front end of the longitudinal beam (7-4-1);
performing frequency sweeping operation on the T-shaped cantilever beam probe through a frequency sweeping vibration exciter to obtain a first-order bending resonance frequency and a first-order torsion resonance frequency of the T-shaped cantilever beam probe;
the method comprises the steps that the T-shaped cantilever beam probe is mechanically excited under the first-order bending resonance frequency through piezoelectric ceramics, a laser force measuring system is used for detecting resonance signals generated by the T-shaped cantilever beam probe, and the normal amplitude of the T-shaped cantilever beam probe is obtained through a phase-locked amplifier, so that a sample to be detected is close to the T-shaped cantilever beam probe in the Z-axis direction until the normal amplitude of the T-shaped cantilever beam probe is equal to a set normal amplitude value;
then, under the current relative position relationship between the sample to be detected and the T-shaped cantilever beam probe, applying alternating current voltage and direct current compensation voltage under first-order torsional resonance frequency between the sample to be detected and the T-shaped cantilever beam probe, obtaining the torsional amplitude of the T-shaped cantilever beam probe through another phase-locked amplifier, then obtaining a relationship curve of the direct current compensation voltage and the torsional amplitude, and selecting a torsional amplitude set value for the Kelvin controller based on the relationship curve;
the torsional amplitude output by the other phase-locked amplifier is used as a feedback signal, the Kelvin controller controls the direct-current power supply to output direct-current compensation voltage to act between the sample to be detected and the T-shaped cantilever beam probe, so that the torsional amplitude output by the other phase-locked amplifier is equal to a set value of the torsional amplitude, and the local surface potential difference U between the sample to be detected and the T-shaped cantilever beam probe is realizedCPDCompensation of (2);
obtaining the local surface potential difference U between the sample to be detected and the T-shaped cantilever beam probe according to the relation curve of the DC compensation voltage and the torsional amplitude of the T-shaped cantilever beam probeCPD；
Recording the coordinates of a Kelvin scanning sample stage where a sample to be tested is located and the local surface potential difference U in the process of testing the scanning test points one by oneCPDAnd the measurement of the sample to be measured is realized.
CN201911313094.7A 2019-12-18 2019-12-18 Kelvin probe force microscope measuring method based on T-shaped cantilever beam probe Active CN110907663B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911313094.7A CN110907663B (en) 2019-12-18 2019-12-18 Kelvin probe force microscope measuring method based on T-shaped cantilever beam probe

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911313094.7A CN110907663B (en) 2019-12-18 2019-12-18 Kelvin probe force microscope measuring method based on T-shaped cantilever beam probe

Publications (2)

Publication Number Publication Date
CN110907663A true CN110907663A (en) 2020-03-24
CN110907663B CN110907663B (en) 2021-12-21

Family

ID=69826453

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911313094.7A Active CN110907663B (en) 2019-12-18 2019-12-18 Kelvin probe force microscope measuring method based on T-shaped cantilever beam probe

Country Status (1)

Country Link
CN (1) CN110907663B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111398638A (en) * 2020-03-30 2020-07-10 哈尔滨工业大学 Kelvin probe force microscope system based on orthogonal probe and sample side wall scanning method
CN113030602A (en) * 2021-03-02 2021-06-25 北京纳米能源与系统研究所 Method, device, equipment and medium for measuring electrical property of sample material
CN114624471A (en) * 2022-03-10 2022-06-14 哈尔滨工业大学 Three-dimensional structure surface measuring method based on three-dimensional Kelvin probe force microscope

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07181028A (en) * 1993-12-22 1995-07-18 Olympus Optical Co Ltd Scanning probe microscope
CN101010751A (en) * 2004-07-08 2007-08-01 里兰斯坦福初级大学理事会 Torsional harmonic cantilevers for detection of high frequency force components in atomic force microscopy
CN102507988A (en) * 2011-10-13 2012-06-20 中山大学 Intermittent-contact-mode measuring method of Kelvin probe force microscope
US20120227139A1 (en) * 2011-03-04 2012-09-06 Masatoshi Yasutake Friction force microscope
CN103429526A (en) * 2011-01-31 2013-12-04 英菲尼特斯马有限公司 Adaptive mode scanning probe microscope
CN106501552A (en) * 2015-09-07 2017-03-15 中国科学院苏州纳米技术与纳米仿生研究所 A kind of while the method for measurement surface magnetic and surface potential
CN106645808A (en) * 2017-02-21 2017-05-10 哈尔滨工业大学 Kelvin probe force microscope synchronously measuring multiple parameters
CN106841687A (en) * 2017-02-21 2017-06-13 哈尔滨工业大学 The method that multi-parameter synchro measure is carried out using Kelvin probe force microscopy
EP3226009A1 (en) * 2016-03-29 2017-10-04 Hitachi High-Tech Science Corporation Scanning probe microscope and probe contact detection method
CN107255738A (en) * 2017-06-23 2017-10-17 电子科技大学 A kind of surface potential measuring method based on Kelvin probe force microscopy
CN107449939A (en) * 2017-08-03 2017-12-08 哈尔滨工业大学 Magnetic drives peak force modulation AFM and multi-parameter method for synchronously measuring

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07181028A (en) * 1993-12-22 1995-07-18 Olympus Optical Co Ltd Scanning probe microscope
CN101010751A (en) * 2004-07-08 2007-08-01 里兰斯坦福初级大学理事会 Torsional harmonic cantilevers for detection of high frequency force components in atomic force microscopy
CN103429526A (en) * 2011-01-31 2013-12-04 英菲尼特斯马有限公司 Adaptive mode scanning probe microscope
US20120227139A1 (en) * 2011-03-04 2012-09-06 Masatoshi Yasutake Friction force microscope
CN102507988A (en) * 2011-10-13 2012-06-20 中山大学 Intermittent-contact-mode measuring method of Kelvin probe force microscope
CN106501552A (en) * 2015-09-07 2017-03-15 中国科学院苏州纳米技术与纳米仿生研究所 A kind of while the method for measurement surface magnetic and surface potential
EP3226009A1 (en) * 2016-03-29 2017-10-04 Hitachi High-Tech Science Corporation Scanning probe microscope and probe contact detection method
CN106645808A (en) * 2017-02-21 2017-05-10 哈尔滨工业大学 Kelvin probe force microscope synchronously measuring multiple parameters
CN106841687A (en) * 2017-02-21 2017-06-13 哈尔滨工业大学 The method that multi-parameter synchro measure is carried out using Kelvin probe force microscopy
CN107255738A (en) * 2017-06-23 2017-10-17 电子科技大学 A kind of surface potential measuring method based on Kelvin probe force microscopy
CN107449939A (en) * 2017-08-03 2017-12-08 哈尔滨工业大学 Magnetic drives peak force modulation AFM and multi-parameter method for synchronously measuring

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
H. XIE ET AL.: "Multiparametric Kelvin Probe Force Microscopy for the Simultaneous Mapping of Surface Potential and Nanomechanical Properties", 《LANGMUIR》 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111398638A (en) * 2020-03-30 2020-07-10 哈尔滨工业大学 Kelvin probe force microscope system based on orthogonal probe and sample side wall scanning method
CN113030602A (en) * 2021-03-02 2021-06-25 北京纳米能源与系统研究所 Method, device, equipment and medium for measuring electrical property of sample material
WO2022183787A1 (en) * 2021-03-02 2022-09-09 北京纳米能源与系统研究所 Method and apparatus for measuring electrical properties of sample material, and device and medium
CN113030602B (en) * 2021-03-02 2022-10-21 北京纳米能源与系统研究所 Method, device, equipment and medium for measuring electrical property of sample material
CN114624471A (en) * 2022-03-10 2022-06-14 哈尔滨工业大学 Three-dimensional structure surface measuring method based on three-dimensional Kelvin probe force microscope

Also Published As

Publication number Publication date
CN110907663B (en) 2021-12-21

Similar Documents

Publication Publication Date Title
CN110907663B (en) Kelvin probe force microscope measuring method based on T-shaped cantilever beam probe
CN106645808B (en) A kind of Kelvin probe force microscopy of multi-parameter synchro measure
CN106841687B (en) The method that multi-parameter synchro measure is carried out using Kelvin probe force microscopy
US4724318A (en) Atomic force microscope and method for imaging surfaces with atomic resolution
USRE33387E (en) Atomic force microscope and method for imaging surfaces with atomic resolution
US7748260B2 (en) Thermal mechanical drive actuator, thermal probe and method of thermally driving a probe
CN107449939B (en) Multi-parameter synchronous measurement method by adopting magnetic drive peak force modulation atomic force microscope
CN111398638B (en) Kelvin probe force microscope system and sample side wall scanning method
US20040069944A1 (en) Balanced momentum probe holder
JPS62130302A (en) Method and device for forming image of surface of sample
JPH07318568A (en) Scanning probe microscope
JP2010508502A (en) Probe assembly for scanning probe microscope
JP5340119B2 (en) Proximity method of probe and sample in scanning probe microscope
US7861577B2 (en) Electric potential difference detection method and scanning probe microscope
CN107085127B (en) A kind of detection method and system of novel scanning probe microscopy
WO2018029151A1 (en) Scanning probe microscope and method for examining a sample surface
CN110082568A (en) A kind of scan-type electrochemical microscope and its bearing calibration
JPH0412547A (en) Film thickness distribution measuring device
JP3106239B2 (en) Probe scanning device
JP4342739B2 (en) Scanning probe microscope
Li et al. Development of a multi-functional multi-probe atomic force microscope system with optical beam deflection method
CN114624471A (en) Three-dimensional structure surface measuring method based on three-dimensional Kelvin probe force microscope
JP3128512B2 (en) Probe scanning device
CN114155219B (en) Method for measuring pressure and electric shear stack high-frequency motion displacement based on AFM knocking processing track
JP4497665B2 (en) Probe scanning control device, scanning probe microscope using the scanning control device, probe scanning control method, and measurement method using the scanning control method

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