Nanostructure Transistor Superlattices for Dopant Blocking and Mobility
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Solution Overview
Problem
Current semiconductor devices face limitations in enhancing charge carrier mobility and reducing scattering effects, despite existing advancements in strained materials and superlattice structures.
Innovation Solution
The semiconductor device incorporates a superlattice structure with alternating layers of semiconductor materials, including dopant blocking superlattices and buffer layers, which reduce charged impurity concentration and improve interface quality, thereby enhancing charge carrier mobility and providing piezoelectric, pyroelectric, and ferroelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor structures are used, then manufacturing is simpler, but charge carrier mobility is limited due to scattering effects from charged impurities and poor interface quality
Solution Approach 1:
The semiconductor structure is divided into multiple alternating layers of different materials (e.g., Si/SiGe, Si/SiO2) forming a superlattice. Each layer is thinner than the depletion width, creating discrete regions that independently contribute to dopant blocking and interface quality enhancement, thereby improving charge carrier mobility through reduced scattering while maintaining manageable manufacturing complexity
Solution Approach 2:
The superlattice introduces localized regions with specific properties: alternating semiconductor layers provide dopant blocking at interfaces, while insulating layers enhance interface quality. This local differentiation of material properties within the channel region reduces charged impurity concentration and scattering effects, improving charge carrier mobility without requiring complete structural redesign
2Reliability
If dopant blocking structures are added to reduce charged impurity concentration, then charge carrier mobility improves, but manufacturing complexity increases
Solution Approach 1:
The dopant blocking function is merged with the superlattice structure itself. The alternating semiconductor and insulating layers in the superlattice simultaneously provide mechanical support, electrical isolation, and dopant blocking through their interfaces. This consolidation of multiple functions into a single integrated structure improves charge carrier mobility while avoiding the need for separate dopant blocking layers, thereby managing manufacturing complexity
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
The superlattice structure achieves higher charge carrier mobility by reducing scattering effects and improving interface quality, leading to enhanced performance in semiconductor devices, including improved mobility and reduced defect density.
Implementation Method 1
The superlattice structure achieves higher charge carrier mobility by reducing scattering effects and improving interface quality
Implementation Method 2
improve mobility and provide piezoelectric, pyroelectric, and ferroelectric properties
Implementation Method 3
improve mobility and provide piezoelectric, pyroelectric, and ferroelectric properties
Implementation Method 4
improve mobility and provide piezoelectric, pyroelectric, and ferroelectric properties
Data Source
AI summary
A semiconductor device may include a substrate and spaced apart gate stacks on the substrate defining respective trenches therebetween. Each gate stack may include alternating layers of first and second semiconductor materials, with the layers of the second semiconductor material defining nanostructures. The semiconductor device may further include respective source/drain regions within the trenches, respective insulating regions adjacent lateral ends of the layers of the first semiconductor material, and respective dopant blocking superlattices adjacent lateral ends of the nanostructures and flush with adjacent surfaces of the insulating regions. Each dopant blocking superlattice may include stacked groups of layers, with each group of layers including a plurality of stacked base semiconductor monolayers defining a base semiconductor portion, and at least one non-semiconductor monolayer constrained within a crystal lattice of adjacent base semiconductor portions.