Semiconductor Device Embedded Layers Inhibit Impurity Diffusion
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Solution Overview
Problem
In semiconductor devices, the diffusion of impurities from the substrate to the semiconductor layer can lead to a deterioration of transistor withstand voltage during the manufacturing process, affecting the device's performance.
Innovation Solution
A semiconductor device configuration where a first electrically conductive type semiconductor layer is formed over a base substrate with a second electrically conductive type embedded layer deeper than the first embedded layer, having a lower impurity concentration, is used to inhibit impurity diffusion and maintain transistor withstand voltage. This configuration includes forming a second embedded layer with a lower impurity concentration than the first embedded layer, which is kept away from the first embedded layer, and a transistor is formed in the semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a diffusion layer is embedded into the semiconductor layer and a transistor is formed over the diffusion layer, then the transistor can be fabricated with proper doping profiles, but impurities may diffuse from the substrate to the semiconductor layer causing deterioration of transistor withstand voltage
Solution Approach 1:
The patent segments the semiconductor layer into multiple regions with different impurity concentrations: a first semiconductor layer with higher impurity concentration and a second semiconductor layer with lower impurity concentration. This segmentation allows the higher impurity region to provide proper doping for transistor fabrication while the lower impurity region prevents impurity diffusion that would deteriorate transistor withstand voltage.
Solution Approach 2:
The patent applies local quality by creating distinct regions within the semiconductor layer with different impurity concentrations tailored to specific functional requirements. The first semiconductor layer region has higher impurity concentration localized where doping is needed for transistor operation, while the second semiconductor layer region has lower impurity concentration localized where impurity diffusion must be prevented to maintain withstand voltage.
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 effectively prevents impurity diffusion from the substrate to the semiconductor layer, thereby maintaining the transistor's withstand voltage and ensuring the semiconductor device's reliability.
Implementation Method 1
Since impurities are also introduced into the substrate however, there has been the possibility that the impurities diffuse from the substrate to the semiconductor layer in the manufacturing process of a semiconductor device and the withstand voltage of the transistor deteriorates
Data Source
AI summary
The present invention makes it possible, in a manufacturing process of a semiconductor device, to inhibit: impurities from diffusing from a substrate to a semiconductor layer; and the withstand voltage of a transistor from deteriorating.In the present invention, a first electrically conductive type epitaxial layer is formed over a first electrically conductive type base substrate. The impurity concentration of the epitaxial layer is lower than that of the base substrate. A second electrically conductive type first embedded layer and a second electrically conductive type second embedded layer are formed in the epitaxial layer. The second embedded layer is deeper than the first embedded layer, is kept away from the first embedded layer, and has an impurity concentration lower than the first embedded layer. A transistor is further formed in the epitaxial layer.