Germanium Passivation via Vapor Phase Monolayers
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Solution Overview
Problem
The challenge in semiconductor devices using germanium substrates is the formation of an ill-defined dielectric oxide interface, which leads to a high density of trapped states and degrades device performance, as existing methods struggle to efficiently remove oxygen and form a high-quality passivation layer.
Innovation Solution
In-situ removal of surface germanium oxide using vapor phase passivants like sulfur, selenium, or nitrogen to form molecular monolayers as a passivation layer, preventing re-oxidation and improving the germanium-oxide interface quality, along with the formation of low-k and high-k interlayers and metal contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If germanium substrate is used to achieve high carrier mobility, then device speed and performance are improved, but the formation of ill-defined dielectric oxide interface with high density of trapped states occurs, degrading device performance
Solution Approach 1:
The patent applies preliminary action by performing in-situ surface modification and passivation layer formation immediately before device fabrication. The germanium surface is treated with vapor phase passivants (SF6, SE6, or N2O) to remove oxygen and form a controlled passivation layer before any subsequent processing, preventing re-oxidation and ensuring high interface quality from the outset
Solution Approach 2:
The patent changes the chemical state of the germanium surface by introducing vapor phase passivants that transform the surface chemistry. The treatment modifies the surface from an oxidized state with trapped states to a passivated state with molecular monolayers, fundamentally changing the interface properties to achieve both high mobility and low trapped state density
2Manufacturing precision
If conventional methods are used to remove germanium oxide, then some oxide removal is achieved, but the methods are cumbersome, inefficient for large-scale manufacturing, and lead to partial reformation of the oxide layer
Solution Approach 1:
The patent replaces mechanical or wet chemical cleaning methods with a vapor phase chemical treatment. Instead of using liquid chemicals or physical removal techniques, the invention uses vapor phase passivants (SF6, SE6, or N2O) that chemically modify and remove oxygen from the surface, providing a more efficient and manufacturable process
Solution Approach 2:
The patent uses an inert vapor atmosphere (SF6, SE6, or N2O) to perform the surface treatment in a controlled environment that prevents re-oxidation. The vapor phase process occurs in a sealed chamber where the inert atmosphere protects the treated surface throughout the manufacturing process, enabling scalable production
3Ease of manufacture
If oxygen is not removed from germanium interface, then processing is simpler, but the ill-defined dielectric oxide interface forms with high density of trapped states that significantly degrade device performance
Solution Approach 1:
The patent introduces vapor phase passivants (SF6, SE6, or N2O) as intermediary substances that mediate the removal of oxygen from the germanium interface. These passivants act as intermediaries that chemically react with and remove oxygen, forming a controlled passivation layer that improves interface quality without complicating the overall manufacturing process
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 removes oxygen from the germanium-oxide interface, forming a high-quality passivation layer that enhances device performance by reducing trapped states and avoiding re-oxidation, making it suitable for both gate and contact applications in semiconductor devices.
Implementation Method 1
In-situ removal of surface germanium oxide using vapor phase passivants like sulfur, selenium, or nitrogen to form molecular monolayers as a passivation layer
Implementation Method 2
exposing in-situ the Ge substrate with the halogen terminated Ge surface to one or more vapor phase passivants to remove at least a part of remaining oxygen
Data Source
AI summary
Embodiments herein describe techniques for a semiconductor device including a Ge substrate. A passivation layer may be formed above the Ge substrate, where the passivation layer may include one or more molecular monolayers with atoms of one or more group 15 elements or group 16 elements. In addition, a low-k interlayer may be above the passivation layer, and a high-k interlayer may be above the low-k interlayer. Furthermore, a metal contact may be above the high-k interlayer. Other embodiments may be described and/or claimed.