Epitaxial III-V Layer Formation on Semiconductor Substrates
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Solution Overview
Problem
The formation of epitaxial III-V layers on semiconductor substrates is hindered by native oxide layers, which are not desirable and can reform during processing, requiring effective removal and prevention methods to ensure clean substrate surfaces.
Innovation Solution
A method involving plasma processing in a pre-clean chamber to remove native oxide layers and replace them with a passivation layer, followed by controlled temperature and precursor flow in an oxygen-free environment to form and grow the III-V layer without heating the substrate above 700°C, ensuring a clean and oxide-free surface for epitaxial growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is heated to high temperature for epitaxial growth, then the quality of the III-V layer is improved, but the risk of oxide reformation increases and thermal budget increases
Solution Approach 1:
The process is divided into distinct stages: pre-cleaning at moderate temperature, cooling in oxygen-free environment, then selective heating only during precursor flow. This segmentation allows quality growth while minimizing oxide reformation risk by limiting high-temperature exposure time
Solution Approach 2:
The substrate is pre-cleaned with plasma at moderate temperature (below 700°C) to remove native oxide before epitaxial growth. This preliminary action creates a clean surface that reduces the tendency for oxide reformation during subsequent processing
2Object-affected harmful factors
If the substrate is cooled quickly after pre-cleaning, then oxide reformation is prevented, but the process time increases
Solution Approach 1:
The substrate is cooled and transported in an oxygen-free environment (inert atmosphere) between pre-cleaning and epitaxial growth. This prevents oxide reformation during the cooling and transport phases without requiring extended cooling times
3Manufacturing precision
If plasma processing is used to remove native oxide, then the substrate surface is cleaned effectively, but the substrate temperature increases
Solution Approach 1:
The pre-cleaning plasma process is conducted at controlled moderate temperatures (below 700°C) rather than high temperatures. This parameter change allows effective oxide removal while limiting temperature increase, and the substrate is subsequently cooled before epitaxial growth
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 effectively removes native oxide layers, prevents reformation, and allows for the growth of high-quality epitaxial III-V layers with controlled thermal budgets, enhancing throughput and reducing costs while maintaining the integrity of the substrate surface.
Implementation Method 1
a native oxide layer may be removed from a substrate in a pre-clean chamber, for example using a plasma (e.g., a hydrogen plasma)
Implementation Method 2
the substrate may be heated from T2 to a third temperature, T3, and then cooled from T3 to a fourth temperature, T4
Implementation Method 3
forming an epitaxial III-V layer on a substrate
Implementation Method 4
a group V precursor may be flowed into the deposition chamber to transform the hydrogen terminated (Si-H) surface into an Arsenic terminated (Si-As) surface
Data Source
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AI summary
Described herein are techniques for forming an epitaxial III-V layer on a substrate. In a pre-clean chamber, a native oxygen layer may be replaced with a passivation layer bytreating the substrate with a hydrogen plasma (or products of a plasma decomposition). In a deposition chamber, the temperature of the substrate may beelevated to a temperature less than 700°C. While the substrate temperature is elevated, a group V precursor may beflowed into the deposition chamber in order to transform the hydrogen terminated (Si-H) surface of the passivation layer into an Arsenic terminated (Si-As) surface. After the substrate has been cooled, a group III precursor and the group V precursor may beflowed in order to form a nucleation layer. Finally, at an elevated temperature, the group III precursor and group V precursor may beflowed in order to form a bulk III-V layer.