Dislocation Density from Etch Pits
Convert a counted number of etch pits on a measured field area into a dislocation density per square centimeter. Formula: D [1/cm²] = N / (A [µm²]·1e-8), where 1 µm² = 1e-8 cm², N is integer pit count ≥0, A>0 µm². Output D≥0 1/cm²; D=0 when N=0. Assumes each pit corresponds to one threading dislocation, uniform distribution, and accurate field area measurement.
Description
Convert counted etch pits and microscope field area into threading-dislocation density per square centimeter.
Convert a counted number of etch pits on a measured field area into a dislocation density per square centimeter. Formula: D [1/cm²] = N / (A [µm²]·1e-8), where 1 µm² = 1e-8 cm², N is integer pit count ≥0, A>0 µm². Output D≥0 1/cm²; D=0 when N=0. Assumes each pit corresponds to one threading dislocation, uniform distribution, and accurate field area measurement.
When to use Dislocation Density from Etch Pits
- Convert counted etch pits and microscope field area into threading-dislocation density per square centimeter.
- Compare fabrication or device scenarios while holding coefficients and unit conventions constant.
- Check a hand calculation before moving to a higher-fidelity process, circuit, or TCAD model.
How the calculation works
Zero observed pits returns zero observed density, not proof that the true density is zero; sampling confidence depends on inspected area.
density = pit count / (area[µm²]·10⁻8) Interpreting the result
Zero observed pits returns zero observed density, not proof that the true density is zero; sampling confidence depends on inspected area.
Assumptions and limitations
- The method assumes one countable etch pit per relevant dislocation, no overlapping pits, representative fields, and an accurately calibrated area.
- Use parameters measured for the same material, geometry, temperature, and operating regime whenever the result informs engineering work.