Correlative Near-Field Characterizations with KPFM, sMIM and SCM to Characterize the Geometry of a N-Channel Failed SiC JFET

Abstract The growing demand for high-performance power electronic devices in a variety of applications has led to a need for efficient, compact designs with increasingly complex architectures. To achieve this, precise and accurate analysis of the local electrical properties at the nanoscale is required to confirm the doping layer geometries at the end of the process. This study employs non-destructive nanoscale characterization techniques to investigate the local properties of designed and fabricated Silicon Carbide (SiC) power devices based on lateral Junction Field-Effect Transistors (JFETs). The SiC sample under study comprises failed n-type lateral JFET channels fabricated with multiple SiC layers in a mesa structure, featuring varying doping levels and several SiC homojunctions. Various electrical modes based on Atomic Force Microscopy (AFM), including the well-known Kelvin Probe Force Microscopy (KPFM), as well as advanced Scanning Capacitance Microscopy (SCM) and scanning Microwave Impedance Microscopy (sMIM) modes, were employed. These three AFM electrical modes enable the mapping of electrical properties, the identification of junctions and the local doping geometries, which are all crucial for device operation and performance. These approaches are highly effective in resolving small-scale variations within multilayers and in providing clear information on doping concentrations, types and work function differences. Mappings from the three modes are compared in terms of sensitivity and signal-to-noise ratio. The impact of the applied VDC during SCM mode on the characterization of SiC junctions is also highlighted.