Silicon Single Crystal Co-Doping for Resistivity Uniformity
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Solution Overview
Problem
The existing methods for manufacturing silicon single crystals, particularly p-type silicon single crystals, face challenges in controlling resistivity distribution and uniformity, which affects the quality and reliability of semiconductor devices. High demand for silicon single crystals with high resistivity (1000 Ω·cm) requires improved technological solutions to meet these demands.
Innovation Solution
A method involving co-doping boron and phosphorus into the silicon melt, controlling the doping concentration ratio between phosphorus and boron within a specific range (0.23 to 0.45), and adjusting the initial concentration of boron (8.0E12 to 1.5E13 atom/cm3) and oxygen (1.5E17 to 4E17 atom/cm3) to achieve uniform resistivity distribution and improved wafer quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doping methods are used to manufacture p-type silicon single crystals, then boron is doped into the silicon melt, but the resistivity distribution becomes non-uniform and thermal double donors form
Solution Approach 1:
The patent combines boron doping and phosphorus doping into a single co-doping process. By introducing both dopants simultaneously into the silicon melt during crystal growth, the method achieves uniform resistivity distribution while preventing thermal double donor formation that occurs with conventional single-dopant methods
Solution Approach 2:
The patent changes the doping parameters by specifying precise concentration ranges: boron initial concentration of 8.0E12 to 1.5E13 atom/cm³, phosphorus initial concentration of 2.0E12 to 6.75E12 atom/cm³, and a doping concentration ratio (P/B) of 0.23 to 0.45. These parameter optimizations resolve the contradiction between uniformity and reliability
2Manufacturing precision
If high resistivity (1000 Ω·cm) silicon single crystals are demanded, then technological development is required, but existing methods cannot achieve the required quality standards
Solution Approach 1:
The patent achieves high resistivity control (1000 Ω·cm) by optimizing specific parameters: controlling oxygen initial concentration at 1.5E17 to 4E17 atom/cm³ (3-8 ppma), maintaining specific boron and phosphorus concentration ratios, and controlling the doping concentration ratio between 0.23 to 0.45. These parameter changes enable precise resistivity control while managing process complexity
3Manufacturing precision
If oxygen concentration is increased to prevent thermal double donors, then resistivity uniformity improves, but excessive oxygen causes other defects
Solution Approach 1:
The patent optimizes oxygen concentration to a specific range of 1.5E17 to 4E17 atom/cm³ (3-8 ppma). This parameter optimization prevents thermal double donor formation and maintains resistivity uniformity while avoiding excessive oxygen that would cause oxygen-related defects such as precipitates or stacking faults
Solution Approach 2:
The patent uses phosphorus doping as an intermediary mechanism to control resistivity uniformity. By introducing phosphorus alongside boron, the method achieves the desired resistivity distribution without requiring excessive oxygen, thereby avoiding oxygen-related harmful effects
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 approach effectively controls the resistivity distribution of silicon single crystals, enhancing the uniformity and reliability of semiconductor devices by reducing resistivity variations and suppressing the formation of thermal double donors, thereby improving the performance and reliability of semiconductor and electronic devices.
Implementation Method 1
controlling a doping concentration ratio, which is a ratio of an initial concentration of phosphorus to an initial concentration of boron
Implementation Method 2
growing the silicon single crystal based on co-doping boron and phosphorous into the silicon melt
Data Source
AI summary
A method of manufacturing a silicon single crystal includes preparing a silicon melt and growing the silicon single crystal based on co-doping boron and phosphorus into the silicon melt. The growing of the silicon single crystal includes controlling, a doping concentration ratio, which is a ratio of an initial concentration of phosphorus to an initial concentration of boron, to be a particular ratio and controlling the initial concentration of boron to be within a range of about 8.0E12 atom/cm3 to about 1.5E13 atom/cm3.