Overview
IEC 63068-4:2022 defines a non-destructive, reproducible procedure for identifying and evaluating defects in as-grown 4H‑SiC homoepitaxial wafers used for power devices. The standard prescribes a combined method that systematically integrates optical inspection and photoluminescence (PL) imaging to improve accuracy of defect recognition versus single-method inspection. It also includes exemplar optical and PL images (Annex A) to help categorize common defect types such as micropipes, stacking faults, TSD/TED, BPD, particle inclusions and surface scratches.
Key Topics
- Combined inspection principle: capture both optical and PL images, convert images to digital grey-scale (or color), then to binary for analysis.
- Image analysis: measure defect size, shape and mean width (planar/volume defects); compute distribution and defect density within specified wafer areas.
- Parameter setting and procedure: defined steps for configuring imaging and analysis parameters, with a parameter-setting process to ensure reproducibility.
- PL specifics: examples use emissions detected at wavelengths longer than 650 nm; PL images can show enlarged defect footprints due to carrier diffusion in SiC epilayers.
- Limitations and cross-checks: some defects produce similar visual features in a single method-IEC 63068-4 recommends combining methods and, when necessary, additional techniques (e.g., X‑ray) to resolve ambiguity.
- Reporting and precision: the standard specifies precision requirements and mandatory/optional elements for the test report to support traceability and quality control.
- Illustrative annex: Annex A provides optical and PL image examples for defect recognition and classification.
Applications
Who uses IEC 63068-4:2022 and why:
- SiC wafer manufacturers and epitaxy process engineers: to detect and classify as-grown defects and improve epitaxial process control.
- Power device fabs and quality engineers: for incoming wafer inspection, yield improvement and acceptance criteria based on non-destructive recognition.
- Failure analysis and R&D teams: to correlate defect types with device performance and explore mitigation strategies.
- Inspection equipment vendors and test labs: to validate and calibrate combined optical + PL inspection systems against an international procedure.
Practical benefits include more accurate defect detection, improved reproducibility, standardized reporting, and better alignment between inspection results and device yield.
Related Standards
Using IEC 63068-4:2022 supports consistent, non-destructive wafer inspection practices for silicon carbide (SiC) power device manufacturing and quality assurance.