Method of using an atomic force microscope and microscope
First Claim
1. A method of use of an atomic force microscope by means of amplitude modulation, of the type that comprises exciting a natural vibration mode of a microlever (M) of said microscope, arranged on a sample to examine, and analyzing at least the variation in amplitude (Ai) of oscillation of an output signal (Ai cos(ω
-
it−
φ
i)), where t is the time and ω
iis the frequency of the microlever (M), representing the response of the microlever (M) to that excitation, in order to obtain topographical information on that sample, wherein said method further comprises an additional excitation of at least one other natural vibration mode of the microlever (M) such that at least two of said excitations of said natural vibration modes of the microlever (M) are carried out simultaneously, and analyzing at least the variation in phase (φ
i) of an output signal (Ai cos(ω
it−
φ
i)) representing the response of the microlever (M) to said additional excitation, in order to obtain compositional information on said sample is carried out by means of an excitation signal (Ficosω
it) of higher frequency than the frequency of an excitation signal (Ficosω
it) used for obtaining said topographical information.
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Accused Products
Abstract
The invention relates to a method of using an atomic force microscope and to a microscope. The inventive method comprises the following steps consisting in at least performing bimodal excitation of a microlever (M) which is disposed on a sample and analysing at least: the variation in the oscillation amplitude (Ai) of an output signal (Ai cos(ωit−φi)) that is representative of the response from the microlever (M) to the excitation of one of the natural vibration modes thereof, in order to obtain topographic information in relation to the sample; and to the variation in the phase (φj) of an output signal (Aj cos(ωjt−φj)) that is representative of the response from the microlever (M) to the excitation of another natural vibration mode thereof, in order to obtain compositional information in relation to the sample. The inventive microscope is adapted to be used with the aforementioned method.
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Citations
14 Claims
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1. A method of use of an atomic force microscope by means of amplitude modulation, of the type that comprises exciting a natural vibration mode of a microlever (M) of said microscope, arranged on a sample to examine, and analyzing at least the variation in amplitude (Ai) of oscillation of an output signal (Ai cos(ω
-
it−
φ
i)), where t is the time and ω
iis the frequency of the microlever (M), representing the response of the microlever (M) to that excitation, in order to obtain topographical information on that sample, wherein said method further comprises an additional excitation of at least one other natural vibration mode of the microlever (M) such that at least two of said excitations of said natural vibration modes of the microlever (M) are carried out simultaneously, and analyzing at least the variation in phase (φ
i) of an output signal (Ai cos(ω
it−
φ
i)) representing the response of the microlever (M) to said additional excitation, in order to obtain compositional information on said sample is carried out by means of an excitation signal (Ficosω
it) of higher frequency than the frequency of an excitation signal (Ficosω
it) used for obtaining said topographical information. - View Dependent Claims (2, 3, 4, 5, 6)
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it−
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7. An atomic force microscope of the type that comprises at least:
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a microlever (M) to be arranged on a sample, a scanning unit associated with the microlever (M) and adapted for performing a scan with the microlever (M) on the sample or part thereof, an excitation unit adapted for exciting said microlever (M) with an excitation signal (Fi cos ω
it) of frequency substantially equal to that of a natural vibration mode of said microlever (M), said excitation signal (Fi cos ω
it) representing an excitation force,a force detection unit associated with the excitation unit for at least detecting the forces applied to and/or generated in the microlever (M), a detection unit adapted for detecting at least one output signal (Ai cos(ω
it−
(Φ
i)) representing the response of the microlever M to the excitation signal, in order to monitor variations in the amplitude (Ai) of oscillation of the output signal (Ai cos(ω
it−
Φ
i)) when performing the scan in order to obtain topographical information on the sample,an image conversion and processing unit adapted for at least transforming said variations in the amplitude (Ai) of oscillation of the output signal (Ai cos(ω
it−
Φ
i)) into a topographical representation of the sample, anda control unit in communication with the rest of the units of the microscope for at least controlling their functioning, wherein the excitation unit or an additional excitation unit is adapted for additionally and simultaneously exciting the microlever (M) with another excitation signal (Fj cos ω
jt) of frequency substantially equal to that of another natural mode of vibration of said microlever (M), this excitation representing another excitation force, and wherein the excitation unit or the additional excitation unit is adapted for detecting an additional output signal (Aji cos(ω
jit−
Φ
ji)) representing the response of the microlever (M) to the additional excitation, in order to monitor variation in the phase (Φ
jiof the additional output signal (Aji cos(ω
jit−
Φ
ji)) when performing that scan in order to obtain compositional information on the sample. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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Specification