Adaptive XY Scanning

Adaptive XY scanning is a Bruker-proprietary technology that enables faster scanning and less position noise than traditional Closed LoopUses a position sensor to provide feedback on piezo movement in response to an applied voltage. scanning.

Conventional closed-loop XY control, while greatly improving positioning accuracy and scan linearity compared to Open LoopFeedback is disabled to reduce noise and improve data resolution, useful for imaging very small features. Assumes that, once calibrated, the piezo will always move the same amount for a given voltage. operation, has two issues:

• Increased XY position noise: The noise of the sensor is introduced into the feedback loop and propagates to the controller output (this is more prominent with scan sizes less than 500 nm).
• Feedback instability and limited tracking bandwidth: The nature of feedback requires that the tracking bandwidth is well below scanner's resonant frequency in XY direction for conventional Proportional, Integral, DerivativePID closed-loop XY control.

Noise performance and tracking performance are two conflicting goals.

For AFM applications, the scanner is required to track a repetitive raster scan motion while compensating low frequency position errors introduced by creep and thermal drift. Adaptive XY control separates the two requirements with advanced digital signal processing, which results in both Higher Bandwidth Tracking and Improved Position Accuracy.

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