FinFET Gate Oxide Formation via Segmented Silicon Oxidation
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Solution Overview
Problem
Conventional methods for forming high-k gate dielectrics face challenges such as increased gate leakage and reduced quality of oxide layers, leading to performance limitations in semiconductor devices as they scale to smaller dimensions.
Innovation Solution
The process involves forming a sacrificial oxide layer on a silicon germanium substrate, removing it, and then oxidizing the remaining silicon layer to create a high-quality oxygen-containing material, followed by the deposition of a high-k dielectric material using reactive ligands and specific precursors, ensuring controlled oxidation and reduced exposure to atmosphere to prevent over-oxidation and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oxide thickness is reduced to improve capacitance and channel mobility, then device performance improves, but gate leakage increases and device yield decreases
Solution Approach 1:
The patent employs a composite gate dielectric structure consisting of a high-k material layer (such as hafnium oxide, zirconium oxide, or lanthanum oxide) combined with a silicon oxide layer. This composite structure enables the system to achieve high capacitance through the high-k material while the silicon oxide layer provides excellent interface quality and low leakage current, thus resolving the contradiction between improved device performance and maintained device yield.
2Speed
If oxide thickness is reduced to improve capacitance, then channel mobility improves, but oxide quality deteriorates and shorting occurs
Solution Approach 1:
The patent uses a composite structure where the high-k material layer provides the necessary capacitance enhancement for improved channel mobility, while the additional silicon oxide layer ensures high oxide quality with proper interface characteristics. This composite approach allows thin effective oxide thickness without compromising oxide quality, preventing shorting while maintaining manufacturing precision.
3Reliability
If high-k materials are used to reduce effective oxide thickness while limiting gate leakage, then device performance improves, but morphology issues limit the maximization of high-k materials
Solution Approach 1:
The patent introduces a silicon oxide layer as an intermediary between the high-k material and the semiconductor substrate. This intermediary layer serves multiple functions: it provides a high-quality interface that facilitates controlled formation of the high-k material, enables better morphology control during deposition, and allows for optimized thicknesses of both layers to achieve desired electrical characteristics. This mediator approach resolves the manufacturing difficulties associated with direct high-k material formation.
4Ease of manufacture
If conventional oxidation methods are used to form gate oxide, then processing is simpler, but over-oxidation occurs and oxide quality decreases
Solution Approach 1:
The patent segments the oxidation process into two distinct stages: first forming a sacrificial oxide layer of controlled thickness, then removing it to expose the substrate, and finally forming a thin interface oxide layer. This segmented approach allows precise control over the final oxide thickness and quality, preventing over-oxidation while maintaining manageable processing complexity through systematic step-by-step fabrication.
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 produces high-quality gate oxide layers that limit over-oxidation, enhance electrical and thermal performance, and reduce gate leakage, resulting in improved semiconductor device performance and yield.
Implementation Method 1
oxidizing a portion of the silicon layer to form a sacrificial oxide while maintaining a portion of the silicon layer in contact with the semiconductor substrate
Implementation Method 2
oxidizing the portion of the silicon layer in contact with the semiconductor substrate to form an oxygen-containing material
Implementation Method 3
forming a high-k dielectric material overlying the oxygen-containing material
Data Source
AI summary
Processing methods may be performed to produce semiconductor structures that may include a high-k dielectric material. The methods may include forming a silicon layer over a semiconductor substrate. The semiconductor substrate may include silicon germanium. The methods may include oxidizing a portion of the silicon layer to form a sacrificial oxide while maintaining a portion of the silicon layer in contact with the semiconductor substrate. The methods may include removing the sacrificial oxide. The methods may include oxidizing the portion of the silicon layer in contact with the semiconductor substrate to form an oxygen-containing material. The methods may include forming a high-k dielectric material overlying the oxygen-containing material.