Czochralski Single Crystal Silicon Resistivity Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The Czochralski process faces challenges in producing single crystal silicon with low resistivity due to 'cell growth' occurring when a large amount of dopant is added, which inhibits single crystallization and increases internal resistance in semiconductor devices like low voltage power MOSFETs.
Innovation Solution
Controlling the height of the solid-liquid interface during crystal growth, specifically by adjusting the striation height, prevents cell growth and allows for dislocation-free crystal growth even with high dopant concentrations, ensuring single crystal silicon with low resistivity is produced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a relatively large amount of dopant is added to a molten silicon raw material to decrease resistivity, then the resistivity of single crystal silicon decreases, but cell growth occurs during crystal growth which disturbs single crystallization
Solution Approach 1:
The invention changes the key parameter of interface height during crystal growth. By controlling the interface height to be within a specific range (5-15 mm from the seed crystal end), the invention resolves the contradiction between adding dopant for lower resistivity and maintaining single crystallization, preventing cell growth while achieving the desired electrical properties
Solution Approach 2:
The invention implements feedback control by monitoring the interface height during crystal growth and adjusting growth parameters accordingly. The interface height is measured and used as feedback to control the pulling speed and rotation speed, ensuring that cell growth is prevented while maintaining consistent single crystallization quality
2Use of energy by moving object
If a relatively large amount of dopant is added to a molten silicon raw material to reduce resistance of low voltage power MOSFET, then the internal resistance decreases and power consumption decreases, but cell growth occurs which inhibits single crystallization
Solution Approach 1:
By changing and controlling the interface height parameter within a specific range, the invention enables the addition of relatively large amounts of dopant (achieving resistivity of 0.5-2.0 mΩ·cm) without causing cell growth, thus reducing power consumption while maintaining single crystallization
Solution Approach 2:
The invention applies preliminary action by pre-establishing the appropriate interface height range (5-15 mm) before crystal growth begins. This preliminary parameter setting prevents cell growth from occurring in the first place, allowing dopant addition for low power consumption applications while maintaining crystal quality
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
This method enables the reliable production of single crystal silicon with extremely low resistivity without dislocations, reducing power consumption in semiconductor devices and enhancing their performance.
Implementation Method 1
a molten silicon raw material
Implementation Method 2
a solid-liquid interface during crystal growth
Implementation Method 3
cell growth occurs due to constitutional undercooling in crystal growth
Data Source
AI summary
The present invention provides a technique which enables production of single crystal silicon having relatively low resistivity by preventing cell growth during crystal growth from occurring, especially in a case where a relatively large amount of dopant is added to a molten silicon raw material. Specifically, the present invention provides a method of producing single crystal silicon by the Czochralski process, comprising producing single crystal silicon having relatively low resistivity by controlling a height of a solid-liquid interface when the single crystal silicon is pulled up.