Semiconductor Crystal Growth via Suspended Raw Material Dropping
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Solution Overview
Problem
Existing semiconductor crystal production methods face challenges in achieving uniform impurity concentration due to complex temperature control and raw material displacement issues, leading to variations in device properties and reproducibility problems.
Innovation Solution
A method and apparatus that involve a longitudinal container with a seed crystal and impurity-containing melt, where a melt of a dropping raw material block with lower impurity concentration is suspended above and dropped into the seed crystal, allowing for controlled temperature gradients and precise positioning to compensate for impurity concentration changes during crystal growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a raw material is placed in a container above a crucible and melted simultaneously with crystal growth, then changes in impurity concentration can be compensated, but the raw material may sink downward and cause complicated temperature control
Solution Approach 1:
The patent introduces a suspension part that can dynamically adjust the position of the raw material block, allowing it to be suspended at different heights above the crucible. This dynamic positioning system enables controlled dropping of the raw material melt while maintaining stable temperature gradients, resolving the contradiction between achieving uniform impurity concentration and avoiding complicated temperature control
Solution Approach 2:
The suspension part acts as an intermediary mechanism between the raw material block and the crucible. It provides a controlled interface for the raw material to be suspended and dropped, enabling precise control over the melting and incorporation process without requiring complex temperature control of the entire system
2Manufacturing precision
If the raw material block is held by friction with the container, then it can be positioned, but the container may wear and chip
Solution Approach 1:
The suspension part serves as an intermediary that holds the raw material block through a fit structure rather than friction between the raw material and container walls. This intermediary mechanism positions the raw material accurately while preventing direct contact that would cause wear and chipping of the container
Solution Approach 2:
The suspension part creates a stable positioning structure that replicates the desired position of the raw material block without requiring the block to be in direct frictional contact with the container. The fit structure between the suspension part and raw material block ensures accurate positioning while protecting the container from wear
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 enables the production of semiconductor crystals with uniform carrier and impurity concentrations, improving reproducibility and allowing for the growth of large-diameter crystals by maintaining precise control over the dropping speed and temperature gradients.
Implementation Method 1
the temperature of a GaAs melt 27 derived from the GaAs polycrystal is gradually decreased upward from the bottom of crucible 20... a raw material 36 placed in a container 35 is melted from the lower side toward the upper side of container 35
Implementation Method 2
GaAs melt 27 solidifies from its lower side that is in contact with seed crystal 25 located at the bottom of crucible 20 toward its upper side
Implementation Method 3
heater 22d heats B2O3 seal 23. B2O3 is thereby melted to seal heat-resistant container 21
Data Source
AI summary
A method of producing a semiconductor crystal is provided. The method includes the steps of preparing a longitudinal container with a seed crystal and an impurity-containing melt placed in a bottom section and with a suspension part arranged in an upper section and suspending a dropping raw material block made of a semiconductor material having an impurity concentration lower than the impurity concentration of the impurity-containing melt, and creating a temperature gradient in the longitudinal direction of the longitudinal container to melt the dropping raw material block, and solidifying the impurity-containing melt from the side that is in contact with the seed crystal (8) while dropping a produced melt into the impurity-containing melt, thereby producing a semiconductor crystal.