In-situ correlative SEM/KPFM for semiconductor devices and 2D heterostructures

TL;DR

This paper introduces a novel in-situ heterodyne Kelvin probe force microscopy technique inside a SEM, enabling simultaneous surface topography and potential mapping for advanced materials and semiconductor analysis.

Contribution

First demonstration of single-pass heterodyne KPFM inside SEM using piezo-resistive cantilevers with crosstalk mitigation, enhancing correlative surface characterization.

Findings

Achieved high-quality surface potential and topography mapping

Compared operational modes for optimal resolution and sensitivity

Demonstrated workflow on 2D heterostructures and semiconductor circuits

Abstract

Correlative nanoscale surface characterization benefits from simultaneously measuring electronic and structural properties in the same environment, a capability that is essential for modern-day materials science and semiconductor failure analysis. In-situ AFM-SEM measurements facilitated by self-sensing cantilevers offer great potential here; however, they are limited due to their inherent capacitive crosstalk. Here, we demonstrate for the first time the in-situ implementation of single-pass heterodyne Kelvin probe force microscopy inside a scanning electron microscope, using piezo-resistive cantilevers. We overcome the capacitive crosstalk prevalent in piezo-resistive cantilevers by demodulating excitation and detection to simultaneously map surface topography and contact potential difference for correlation with compositional analysis. We systematically compare different operational modes of this heterodyne technique, elucidating their spatial resolution, signal sensitivity, and signal-to-noise ratio. The integrated approach yields exceptional signal quality and reveals how electron beam scan parameters can directly influence surface potential contrast. We demonstrate this correlative analysis workflow on two-dimensional heterostructures and semiconductor circuits. This work establishes a robust and versatile correlative imaging mode for in-situ Kelvin force and topography imaging inside a scanning electron microscope for next-generation semiconductor device analysis and materials science.