corona-kelvin metrology

**Corona-Kelvin Metrology** is a **non-contact technique that combines corona charge deposition with Kelvin probe measurement** — depositing a known charge on the dielectric surface and measuring the resulting surface potential to extract oxide thickness, flatband voltage, interface trap density, and mobile charge. **How Does It Work?** - **Corona Discharge**: Deposit a precise, known charge ($Q$) on the dielectric surface (no metallization needed). - **Kelvin Probe**: Measure the resulting surface potential change $Delta V_s$. - **Sweep**: Deposit increasing charge doses -> plot $V_s$ vs. $Q$ (analog of C-V curve, but without metal contacts). - **Extract**: $C_{ox}$ (oxide thickness), $V_{fb}$ (flatband voltage), $D_{it}$ (interface traps), $Q_f$ (fixed charge). **Why It Matters** - **No Metal Gate**: Characterizes gate dielectric quality without depositing a metal gate (saves process steps). - **In-Line**: Used as an in-line monitor after gate oxidation, before gate metal deposition. - **Production Tool**: Standard production metrology tool (Semilab, KLA) for gate oxide qualification. **Corona-Kelvin** is **the gateless C-V curve** — characterizing dielectric quality by depositing charge instead of fabricating a metal electrode.