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

Three-dimensional semiconductor chip architectures promise high-density memory and much faster computation, but self-heating and leakage currents still severely limit performance. While current-density mapping is crucial to studying these issues in situ, nondestructive imaging has been limited to two dimensions. The authors use ensembles of nitrogen-vacancy centers in diamond as nanoscale quantum sensors to probe all three vectorial components of magnetic fields associated with electric currents, for noninvasive imaging of three-dimensional currents in multilayer integrated circuits. Further improvements could reveal the local conductance of materials, to advance condensed matter physics.