Semiconductor Capping Layer Crystallization for SiGe Oxidation Resistance
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Solution Overview
Problem
The semiconductor industry faces challenges in manufacturing low-cost, high-performance, and low-power integrated circuits due to increased complexity in scaling down semiconductor IC dimensions, which affects the efficiency and cost of production.
Innovation Solution
The method involves forming Fin Field-Effect transistors (FinFETs) and Gate All Around (GAA) transistors using a Si capping layer to protect SiGe from oxidation, achieved through thermal treatment to convert amorphous silicon into crystalline silicon, reducing lattice constant and oxidation rates, and employing multi-patterning processes for precise feature creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If SiGe is used to improve carrier mobility and device performance, then device speed and efficiency are improved, but SiGe is highly susceptible to oxidation which degrades device reliability
Solution Approach 1:
A silicon capping layer is deposited over the SiGe layer to act as a protective intermediary barrier that prevents oxidation of the SiGe. The silicon layer has lower oxidation rate than SiGe and serves as a shield during thermal processing, thereby protecting the underlying SiGe from direct exposure to oxygen while maintaining the performance benefits of SiGe
Solution Approach 2:
The silicon capping layer is formed in advance before any thermal processing or oxidation steps are performed on the SiGe structure. This preliminary protective action prevents oxidation from occurring during subsequent manufacturing processes, ensuring the SiGe maintains its intended properties without degradation
2Productivity
If amorphous silicon is deposited to form the capping layer, then the deposition process is simple and fast, but the capping layer has high oxidation rate and poor protection效果
Solution Approach 1:
The amorphous silicon capping layer undergoes a phase transition from amorphous to crystalline structure through thermal annealing treatment. This phase transition transforms the material properties, resulting in a crystalline silicon layer with lower oxidation rate and improved protective capability while maintaining the original amorphous layer's deposition efficiency advantages
Solution Approach 2:
The crystalline structure of the silicon capping layer is achieved by changing the thermal parameters (temperature and time) during post-deposition processing. By controlling the annealing conditions, the silicon atoms reorganize into a crystalline structure that exhibits superior oxidation resistance compared to the amorphous state, thereby reducing the harmful oxidation effect
3Manufacturing precision
If multi-patterning processes are used to achieve precise feature dimensions, then manufacturing precision is improved, but process complexity and production time increase
Solution Approach 1:
The patterning process is divided into multiple sequential steps, each creating a portion of the final pattern. The multi-patterning approach segments the complex patterning task into manageable stages (such as self-aligned double patterning or triple patterning), where each step contributes to the final precise feature dimensions while maintaining overall process control
Solution Approach 2:
Multiple patterning layers are nested within each other through self-aligned processes, where each subsequent pattern is precisely positioned relative to the previous layer. This nesting approach enables complex multi-layer patterns to be formed with high precision without requiring completely independent alignment steps for each layer
4Productivity
If feature size is scaled down to improve production efficiency and lower costs, then productivity and cost-effectiveness are improved, but manufacturing complexity and process control difficulty increase
Solution Approach 1:
The manufacturing process parameters (such as deposition thickness, etch selectivity, annealing temperature) are precisely adjusted and optimized to accommodate the scaled-down feature dimensions. By changing these parameters, the process maintains control and quality at smaller dimensions, enabling continued scaling while managing the increased manufacturing complexity through parameter optimization
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 enhances the resistance of SiGe to oxidation, reduces defects, and improves fin line edge roughness and N/P fin loading issues, leading to more efficient and cost-effective semiconductor manufacturing.
Implementation Method 1
thermal treatment to convert amorphous silicon into crystalline silicon
Implementation Method 2
Si capping layer to protect SiGe from oxidation, achieved through thermal treatment to convert amorphous silicon into crystalline silicon, reducing lattice constant and oxidation rates
Data Source
AI summary
A method for manufacturing a semiconductor device is provided. The method includes forming at least one epitaxial layer over a substrate; patterning the epitaxial layer into a semiconductor fin; depositing a conformal semiconductor capping layer over the semiconductor fin, wherein the conformal semiconductor capping layer has a first portion that is amorphous; performing a thermal treatment such that the first portion of the conformal semiconductor capping layer is converted from amorphous into crystalline; depositing a dielectric material over the conformal semiconductor capping layer; annealing the dielectric material, such that the conformal semiconductor capping layer is converted into a semiconductor-containing oxide layer; recessing the dielectric material and the semiconductor-containing oxide layer to form an isolation structure around the semiconductor fin; and forming a gate structure over the semiconductor fin and the isolation structure.