microwave impedance microscopy

**Microwave Impedance Microscopy (MIM)** is an **advanced scanning probe technique that measures local electrical impedance at microwave frequencies** — providing nanoscale maps of conductivity, permittivity, and carrier concentration without requiring electrical contact to the sample. **How Does MIM Work?** - **Probe**: An AFM tip connected to a microwave transmission line (1-20 GHz). - **Signal**: The reflected microwave signal is sensitive to the local impedance under the tip. - **Channels**: MIM-Re (resistive component, conductivity) and MIM-Im (capacitive component, permittivity). - **Resolution**: ~50-100 nm spatial resolution for electrical properties. **Why It Matters** - **Non-Contact Electrical**: Maps electrical properties without requiring ohmic contact or sample preparation. - **Buried Features**: Microwave signals penetrate below the surface, imaging buried dopant profiles and structures. - **Failure Analysis**: Can image leakage paths, doping variations, and buried defects in finished devices. **MIM** is **electrical imaging at microwave frequencies** — seeing local conductivity and permittivity with nanoscale resolution using microwave reflections.