Force scanning probe microscope
View Patent ↗A force scanning probe microscope (FSPM) and associated method of making force measurements on a sample includes a piezoelectric scanner having a surface that supports the sample so as to move the sample in three orthogonal directions. The FSPM also includes a displacement sensor that measures movement of the sample in a direction orthogonal to the surface and generates a corresponding position signal so as to provide closed loop position feedback. In addition, a probe is fixed relative to the piezoelectric scanner, while a deflection detection apparatus is employed to sense a deflection of the probe. The FSPM also includes a controller that generates a scanner drive signal based on the position signal, and is adapted to operate according to a user-defined input that can change a force curve measurement parameter during data acquisition.
1. A method of making a force curve measurement on a sample, the method comprising:
providing a probe microscope having a probe;
producing relative motion between the probe and the sample in response to a user-defined input defining intended motion in a direction generally orthogonal to a surface of the sample;
detecting the relative motion and comparing the relative motion to the corresponding intended motion;
measuring a force on the probe when the sample interacts with the probe;
changing a force curve measurement parameter in response to said measuring step; and
wherein the user-defined input defines at least one of multiple approach moves and multiple retract moves in one cycle.
2. The method of claim 1 , further comprising the step of generating relative motion between the probe and the sample in response to said detecting step.
3. The method of claim 1 , wherein said measuring step includes detecting a motion of the probe.
4. The method of claim 1 , wherein said changing step is performed based on the user-defined input.
5. The method of claim 4 , wherein the user-defined input is a path defined by force versus time.
6. The method of claim 5 , further including the step of determining a force gradient based on said measuring step performed for at least two points in time.
7. The method of claim 1 , wherein the force measurement parameter is a speed associated with said producing step.
8. The method of claim 1 , wherein the force curve measurement parameter is pausing said producing step for a predetermined amount of time.
9. The method of claim 1 , wherein said producing step is interrupted prior to said changing step.
10. The method of claim 1 , wherein said measuring step is performed for at least two points in time, and said changing step is performed in response to a predetermined change in the force.
11. The method of claim 1 , wherein said changing step is predetermined.
12. The method of claim 11 , wherein said changing step includes modulating a separation between the sample and the probe so that the measured forces corresponding to a plurality of points in time correspond to a predetermined force profile as a function of time.
13. The method of claim 12 , wherein said modulating step is performed using a force feedback loop.
14. The method of claim 1 , further comprising the step of measuring a separation between the sample and the probe as a function of time.
15. The method of claim 1 , wherein said changing step includes controlling the separation between the probe and the sample according to a user-defined path defined by position versus time.
16. The method of claim 1 , wherein said producing step is performed by a sensored Z stage.
17. The method of claim 1 , wherein the approach and attract moves are each defined by at least one of an associated velocity and an associated direction.
18. A method of making a force curve measurement on a sample, the method comprising:
providing a probe microscope having a probe;
producing relative motion between the probe and the sample in response to a user-defined input defining intended motion in a direction generally orthogonal to a surface of the sample;
detecting the relative motion and comparing the relative motion to the corresponding intended motion;
measuring a force on the probe when the sample interacts with the probe;
changing a force curve measurement parameter in response to said measuring step; and
wherein the force curve measurement parameter is at least one of a direction and a speed associated with said producing step.
19. The method of claim 18 , wherein the user-defined input includes a combination of at least four unique segments over one cycle.
20. The method of claim 19 , wherein each of the at least four unique segments is defined by at least one of an associated velocity and an associated direction.
21. A method of making a force curve measurement on a sample, the method comprising:
providing a probe microscope having a probe;
producing relative motion between the probe and the sample in response to a user-defined input defining intended motion in a direction generally orthogonal to a surface of the sample;
detecting the relative motion and comparing the relative motion to the corresponding intended motion;
measuring a force on the probe when the sample interacts with the probe;
changing a force curve measurement parameter in response to said measuring step;
wherein said producing step is performed by a sensored Z stare; and
wherein said sensored Z stage is coupled to a piezoelectric tube scanner, said tube scanner providing scanning motion in a plane substantially orthogonal to the third axis.