Three-dimensional imaging of integrated-circuit activity using quantum defects in diamond

The continuous scaling of semiconductor-based technologies to micrometer and submicrometer regimes has resulted in higher device density and lower power dissipation. Many physical phenomena such as self-heating or current leakage become significant at such scales, and mapping current densities to reveal these features is decisive for the development of modern electronics. However, advanced noninvasive technologies either offer low sensitivity or poor spatial resolution and are limited to two-dimensional spatial mapping. Here we use near-surface nitrogen-vacancy centers in diamond to probe Oersted fields created by current flowing within a multilayered integrated circuit in predevelopment. We show the reconstruction of the three-dimensional components of the current density with a magnitude down to about ≈10 µA/µ$m^2$ and submicrometer spatial resolution at room temperature. We also report the localization of currents in different layers and observe anomalous current flow in an electronic chip. Our method therefore provides a decisive step toward three-dimensional current mapping in technologically relevant nanoscale electronics chips.