Imaging of Magnetic Field Gradient around a Current Path by Alternating Magnetic Force Microscopy

Abstract

We have developed a multi-function scanning probe microscopy (Multi-SPM) system that integrates FM-AFM/KFM/A-MFM techniques for comprehensive imaging of current path within power semiconductor devices. This advanced Multi-SPM setup enables concurrent visualization of surface morphology, surface potential, and magnetic field intensity gradients. During both non-conduction and conduction of DC current, we were able to simultaneously investigate these parameters in the same spatial region. Notably, the magnetic field intensity gradient distribution accurately captured the static magnetic field generated by the DC current flow. Particular interest is the dynamic variation in intensity and polarity of the H_z component of the magnetic field gradient distribution in response to the conduction of current and its direction. Based on these findings, we can confidently affirm that A-MFM effectively enables the observation of magnetic fields surrounding direct current path.