SiC Epitaxial Wafer Defect Evaluation via Surface and PL Inspection
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Solution Overview
Problem
Current methods for detecting defects in SiC devices, such as photoluminescence measurements, are insufficient in identifying process-related defects like oxide film breakage and defective electric strength, which hinder yield improvement and device efficiency.
Innovation Solution
A manufacturing method for SiC devices that includes an ion implantation process followed by a comprehensive evaluation process involving surface inspection, photoluminescence inspection, and determination of defect severity using surface and PL defect images, with specific criteria for determining defects based on luminance ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If photoluminescence measurement is performed on SiC ingot or wafer, then crystal defects can be detected, but process defects such as oxide film breakage and defective electric strength cannot be specified
Solution Approach 1:
The evaluation process is segmented into three distinct inspection stages: surface inspection to detect physical defects, photoluminescence inspection to detect crystal defects, and electric strength measurement to detect electrical performance defects. Each stage targets specific defect types, allowing comprehensive detection while maintaining measurement precision for each defect category.
Solution Approach 2:
The invention transitions from single-dimension photoluminescence measurement to multi-dimensional evaluation by adding surface inspection (physical dimension) and electric strength measurement (electrical dimension). This multi-dimensional approach enables detection of process defects that cannot be detected by photoluminescence alone.
2Measurement precision
If comprehensive evaluation process is implemented including surface inspection, PL inspection, and determination process, then defect classification accuracy is improved, but manufacturing process complexity increases
Solution Approach 1:
Surface inspection is performed as a preliminary step before photoluminescence inspection and electric strength measurement. Defects are detected and classified in advance, allowing subsequent measurements to be targeted at specific defect locations, thereby improving classification accuracy while managing process complexity through systematic sequencing.
Solution Approach 2:
The determination process uses feedback from surface inspection results to guide photoluminescence inspection and electric strength measurement. Defect images and characteristics from each stage are fed back to refine classification accuracy, creating a closed-loop evaluation system that improves precision without requiring complete re-inspection at each stage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate detection and classification of defects, particularly those causing oxide film breakage and defective electric strength, thereby improving manufacturing yield and device performance.
Implementation Method 1
a PL inspection process of irradiating a region that includes the defect detected in the surface inspection with excitation light to perform photoluminescence measurement after the surface inspection process
Data Source
AI summary
Provided is a manufacturing method for a SiC device including: performing an ion implantation process of implanting ions in an epitaxial layer of a SiC epitaxial wafer that has the epitaxial layer; and performing an evaluation process of evaluating a defect of the SiC epitaxial wafer after the ion implantation process, in which the evaluation process includes a surface inspection process of inspecting a surface of the SiC epitaxial wafer, a PL inspection process of irradiating a region that includes the defect detected in the surface inspection to perform photoluminescence measurement after the surface inspection process, and a determination process of determining a degree of the defect from a surface defect image detected in the surface inspection and a PL defect image detected in the PL inspection process.