Metrology for 2D materials: a perspective review from the international roadmap for devices and systems.

The International Roadmap for Devices and Systems (IRDS) predicts the integration of 2D materials into high-volume manufacturing as channel materials within the next decade, primarily in ultra-scaled and low-power devices. While their widespread adoption in advanced chip manufacturing is evolving, the need for diverse characterization methods is clear. This is necessary to assess structural, electrical, compositional, and mechanical properties to control and optimize 2D materials in mass-produced devices. Although the lab-to-fab transition remains nascent and a universal metrology solution is yet to emerge, rapid community progress underscores the potential for significant advancements. This paper reviews current measurement capabilities, identifies gaps in essential metrology for CMOS-compatible 2D materials, and explores fundamental measurement science limitations when applying these techniques in high-volume semiconductor manufacturing.

A moving window correlation method to reduce the distortion of scanning probe microscope images.

Many scanning probe microscopes such as the scanning tunneling microscope and atomic force microscope use piezoelectric actuators operating in open loop for generating the scans of the surfaces. However, nonlinearities mainly caused by hysteresis and drift of piezoelectric actuators reduce the positioning accuracy and produce distorted images. A moving window correlation method is proposed in this paper to determine and quantify the hysteresis. This method requires both trace and retrace profiles to be recorded. With a window imposed on each of the profiles, correlations are implemented between the data inside two windows to find corresponding pixel pairs on two different profiles but the same physical positions along the fast scanning axis (x). The x-distances between pixel pairs are calculated and then a simple correction scheme is applied to reduce the distortion.