SOI Device BOX Layer Deformation for Carrier Mobility
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Solution Overview
Problem
Current methods for applying stress to the channel area of semiconductor devices using Silicon on Insulator (SOI) substrates do not adequately increase the degree of deformation in the BOX layer, limiting carrier mobility improvements.
Innovation Solution
A semiconductor device and manufacturing method involving an SOI substrate with a BOX layer and SOI layer, where part or all of the BOX layer in non-active areas is removed to allow deformation-induced stress to remain in the BOX layer, facilitating increased stress application to the SOI layer through high-temperature annealing processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stress film is formed on the SOI layer and high-temperature annealing is performed to generate creep in the BOX layer, then stress can be applied to the channel area to improve carrier mobility, but the degree of deformation remaining in the BOX layer is insufficient to further improve carrier mobility
Solution Approach 1:
The patent removes the BOX layer from non-active areas adjacent to the active area where transistors are formed. This extraction allows the BOX layer in the active area to undergo greater deformation during high-temperature annealing, thereby generating sufficient stress in the SOI layer to improve carrier mobility. The selective removal creates a structure where the remaining BOX layer can effectively serve its stress-generation function without being constrained by the full BOX layer structure.
2Stress or pressure
If the BOX layer is removed in non-active areas to increase deformation in the active area, then stress application to the SOI layer is improved, but the structural complexity of the semiconductor device increases
Solution Approach 1:
The patent applies local quality by creating a non-uniform BOX layer structure where the BOX layer is selectively removed from non-active areas while being retained in the active area. This local differentiation allows the BOX layer in the active area to experience greater deformation and generate higher stress in the SOI layer, while the overall device structure remains manageable. The local modification optimizes stress generation without requiring complete structural redesign.
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 carrier mobility by applying stress exceeding 100 MPa to the SOI layer, improving electron mobility and reducing on-resistance in transistors, while allowing for various electronic apparatus applications such as displays and image sensors.
Implementation Method 1
generating deformation caused by a creep on the BOX layer by executing high annealing
Implementation Method 2
executing high annealing to generate deformation caused by creep in the BOX layer
Data Source
AI summary
A semiconductor device formed by using an SOI substrate including a substrate, a BOX layer formed on the substrate, and an SOI layer formed on the BOX layer, in which a part of or all of the BOX layer at least in a part of the BOX layer arranged in a non-active area adjacent to an active area has been removed, and the BOX layer in a portion where the SOI layer forming the active area is arranged is configured to remain deformation used to apply stress to the SOI layer.