Silicon Single-Crystal Resistivity Measurement After Oxide Removal
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Solution Overview
Problem
Existing methods for measuring the resistivity of nitrogen-added silicon single crystals with resistivity of 100 Ωcm or higher, such as those grown by the MCZ method, fail to accurately determine the resistivity derived from dopants due to the formation of thermal oxide films and nitrogen donor annihilation during heat treatment, leading to significant deviations in resistivity measurements.
Innovation Solution
Perform oxidation heat treatment at 1100 to 1250° C. for 90 to 240 minutes on the silicon single crystal substrate to form a thermal oxide film, then remove it using hydrofluoric acid etching and grinding to eliminate the effect of nitrogen donors and thermal oxide film on resistivity measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If heat treatment is performed on nitrogen-added silicon single crystal to annihilate nitrogen donors, then resistivity measurement accuracy improves, but thermal oxide film forms on substrate surface causing measurement deviation
Solution Approach 1:
The patent applies preliminary action by performing oxidation heat treatment at controlled temperatures (900-1250°C) for specific durations (30-480 minutes) to annihilate nitrogen donors before resistivity measurement. This pre-treatment eliminates the harmful effect of nitrogen donors on measurement accuracy, while the subsequent removal of formed oxide films ensures no measurement deviation occurs.
Solution Approach 2:
The patent utilizes parameter changes by systematically varying heat treatment temperature and time parameters to achieve optimal nitrogen donor annihilation. By controlling these parameters, the patent balances the annihilation effect with minimal oxide film formation, resolving the contradiction between measurement accuracy improvement and harmful film formation.
2Reliability
If nitrogen is added to suppress dislocation and slip during high-temperature processing, then manufacturing reliability improves, but nitrogen donors remain in as-grown crystal causing resistivity deviation
Solution Approach 1:
The patent applies preliminary action by implementing oxidation heat treatment as a pre-measurement step to annihilate nitrogen donors that were intentionally added to suppress dislocation. This pre-treatment removes the harmful residual effect of nitrogen donors on resistivity measurement accuracy while preserving the reliability benefits of nitrogen addition during crystal growth and processing.
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 precise measurement of resistivity derived from dopants in nitrogen-added silicon single crystals with high resistivity by annihilating nitrogen donors and removing the thermal oxide film, ensuring accurate resistivity determination.
Implementation Method 1
performing oxidation heat treatment at a temperature of 1100 to 1250° C. for 90 to 240 minutes on a substrate sliced from the silicon single crystal to form a thermal oxide film on a surface of the substrate
Implementation Method 2
performing oxidation heat treatment at a temperature of 1100 to 1250° C. for 90 to 240 minutes
Implementation Method 3
measuring resistivity of the substrate after removing the thermal oxide film from the surface of the substrate
Data Source
AI summary
The present invention is a method for measuring resistivity of a silicon single crystal with resistivity of 100 Ωcm or higher, the silicon single crystal being grown with addition of nitrogen by an MCZ method, the method including: performing oxidation heat treatment at a temperature of 1100 to 1250° C. for 90 to 240 minutes on a substrate sliced from the silicon single crystal to form a thermal oxide film on a surface of the substrate; and measuring resistivity of the substrate after removing the thermal oxide film from the surface of the substrate. This provides a method for measuring resistivity of a silicon single crystal is provided which can measure a precise resistivity derived from a dopant for a silicon single crystal with resistivity of 100 Ωcm or higher that is grown with addition of nitrogen by the MCZ method.