Semiconductor Doping Layers for Independent Depth and Concentration Control
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Solution Overview
Problem
Current semiconductor doping methods, such as diffusion and ion implantation, face challenges in achieving precise control over dopant concentration and depth, especially in complex 3D structures like super-junction MOSFETs, where accurate doping profiles are necessary for modern electronic applications.
Innovation Solution
A semiconductor doping method involving a separation layer and a mixture material source layer with a specific molecular structure, deposited using atomic layer deposition, where the separation layer is void of dopants and distances the dopant source further from the substrate, allowing for precise tuning of the doping profile through annealing at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If diffusion doping is used to achieve isotropic doping in complex 3D structures, then doping uniformity across various spatial features is improved, but control over doping concentration and depth becomes insufficient
Solution Approach 1:
The dopant source is segmented into multiple distinct layers: a first dopant source layer containing dopant atoms and a second dopant source layer containing a different dopant substance. This segmentation allows independent control of doping concentration and depth profiles by adjusting the thickness and composition of each layer separately, resolving the contradiction between achieving uniform isotropic doping and maintaining precise control over doping parameters.
Solution Approach 2:
The patent employs composite dopant source structures combining different dopant materials (e.g., phosphorous oxide and silicon oxide in alternating layers) to achieve tailored doping profiles. The composite structure enables independent optimization of concentration and depth characteristics that cannot be achieved with single-material sources, while maintaining the isotropic diffusion behavior needed for complex 3D structures.
2Manufacturing precision
If ion implantation is used to control doping concentration independently of depth, then doping profile precision is improved, but applicability to complex 3D structures deteriorates due to anisotropic behavior
Solution Approach 1:
The patent replaces the mechanical/ion-beam-based implantation process with a thermal diffusion process. Instead of using directed ion beams that exhibit anisotropic behavior, the invention uses thermally activated diffusion from solid-state dopant source layers, which naturally provides isotropic doping distribution. This substitution maintains precise concentration control through layer thickness design while achieving the adaptability needed for complex 3D structures.
3Ease of operation
If conventional diffusion doping is used with solid state dopant sources, then isotropic doping is achieved, but control over doping concentration becomes insufficient
Solution Approach 1:
The dopant source is divided into multiple discrete layers with controlled thicknesses and compositions. By adjusting the thickness of each dopant source layer, the doping concentration can be precisely controlled while maintaining isotropic diffusion characteristics. The segmented structure allows independent tuning of concentration and depth parameters that were previously coupled in conventional single-layer diffusion processes.
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 enables independent control of doping depth and concentration, achieving accurate and uniform dopant distribution across various spatial features from nanometer to decimeter scales, addressing the limitations of existing methods in complex 3D structures.
Implementation Method 1
arrange diffusion of dopant substance from the mixture material source layer to the substrate and to the separation layer
Implementation Method 2
annealing the substrate, the separation layer, and the mixture material source layer in an annealing step, in which the substrate, the separation layer, and the mixture material source layer are heated to an elevated temperature
Implementation Method 3
depositing a separation layer on the surface of a substrate in a separation layer deposition step... depositing a mixture material source layer in a mixture material source layer deposition step
Data Source
AI summary
The method for doping a semiconductor includes the following steps in the following order: separation layer deposition step, in which a separation layer is deposited on the surface of a substrate, a mixture material source layer deposition step, in which a mixture material source layer including a mixture material is deposited on the separation layer, the mixture material of the mixture material source layer including a dopant substance, and annealing the substrate, the separation layer, and the mixture material source layer in an annealing step to arrange diffusion of dopant substance from the mixture material source layer to the substrate and to the separation layer.