III-V Semiconductor Nanowire Shell Growth via Temperature Gradient
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Solution Overview
Problem
The manufacturing methods for optoelectronic devices with three-dimensional semiconductor elements, such as microwires and nanowires, often result in uneven lateral surfaces of the shell, leading to defects and reduced conversion efficiency due to impurity accumulation during the growth process, which complicates large-scale and cost-effective production.
Innovation Solution
A method involving continuous growth in a reactor with varying temperature and gas ratios (V/III, H2/N2) to promote the growth of crystallographic planes parallel and perpendicular to the axis, reducing the shell's lateral bulk and minimizing defects by uninterrupted precursor gas flow, allowing for the formation of uniform semiconductor elements with improved active areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the growth of semiconductor elements is interrupted before shell growth begins, then impurity accumulation on lateral surfaces increases, but continuous growth increases manufacturing time
Solution Approach 1:
The patent implements continuous growth of semiconductor elements without interruption before shell formation. The temperature is maintained in a range (900-1100°C) that promotes axial growth while suppressing lateral growth, allowing continuous operation without impurity accumulation issues that would arise from stopping and restarting the process
Solution Approach 2:
The patent changes the temperature parameter during the growth process. By maintaining temperature between 900-1100°C during axial growth and then reducing it to 800-950°C for shell formation, the process achieves both continuous operation and high-quality shell growth without impurity accumulation
2Productivity
If temperature is maintained high during growth, then axial growth is promoted, but lateral surfaces become uneven leading to shell defects
Solution Approach 1:
The patent dynamically adjusts the temperature parameter during the growth process. High temperature (900-1100°C) is used during axial growth phase to maximize growth speed, then temperature is reduced (800-950°C) during shell formation phase to ensure uniform lateral surfaces and prevent defects
Solution Approach 2:
The patent changes temperature parameters between different growth phases. The temperature is maintained at 900-1100°C for axial growth promotion, then reduced to 800-950°C for shell growth to achieve uniform lateral surfaces, resolving the contradiction between growth speed and surface uniformity
3Reliability
If shell lateral bulk is reduced, then conversion efficiency improves, but shell formation becomes more difficult
Solution Approach 1:
The patent uses temperature reduction to 800-950°C during shell formation to achieve thin lateral bulk while maintaining uniform growth. This temperature parameter change enables precise control over shell thickness, making thin-shell formation easier while improving conversion efficiency
Solution Approach 2:
The patent employs periodic action by using two distinct temperature phases: high temperature (900-1100°C) for axial growth and lower temperature (800-950°C) for shell formation. This periodic temperature control enables both thin shell formation and ease of manufacture
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 decreases the number of defects in the shell, reduces manufacturing time, and enables the production of optoelectronic devices at an industrial scale with enhanced efficiency and lower costs by ensuring continuous growth conditions that prevent impurity accumulation and promote uniform crystallographic plane formation.
Implementation Method 1
the temperature in the reactor varies, along the continuous growth of the portions, uninterruptedly from a first temperature value which promotes the growth of first crystallographic planes perpendicular to said axis to a second temperature value, lower than the first temperature value, which promotes the growth of second crystallographic planes parallel to said axis
Implementation Method 2
The method generally comprises introducing into the reactor precursor gases of the III-V compound by proportions which favor the growth of each semiconductor element preferentially along an axis
Data Source
AI summary
The invention relates to a method for manufacturing an optoelectronic device (50) including wire-like, conical, or frustoconical semiconductor elements (20) predominantly comprising a III-V compound. Each semiconductor element extends along an axis and includes a portion (54), the side surfaces (55) of which are covered with a shell (56) including at least one active region (31), wherein the portions are created by continuous growth in a reactor, and wherein the temperature in the reactor varies in an uninterrupted manner from a first temperature value that favors growth of first crystallographic planes perpendicular to said axis, to a second temperature value that is strictly lower than the first temperature value and favors growth of second crystallographic planes parallel to said axis.