Multi-Layer Memory Device Doping Uniformity
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Solution Overview
Problem
The challenge in semiconductor devices is the limited thickness of semiconductor layers compared to substrates, leading to non-uniform properties and increased electrical resistance, which affects the uniformity and performance of multi-layer nonvolatile memory devices.
Innovation Solution
Increasing the doping concentration of well regions in semiconductor layers to match or exceed that of the substrate, thereby reducing resistance differences and improving uniformity by forming semiconductor layers with higher surface doping concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a semiconductor layer is formed on a semiconductor substrate to create a multi-layer structure, then the horizontal size limit is overcome and three-dimensional stacking is achieved, but the semiconductor layer thickness is limited compared to the substrate thickness, resulting in non-uniform device properties
Solution Approach 1:
The patent applies local quality by forming a well region with higher doping concentration specifically in the semiconductor layer where cell arrays are formed, rather than uniformly doping the entire structure. This localized doping adjustment compensates for the thickness limitation of the semiconductor layer, ensuring that devices in the layer have properties uniform with devices in the substrate.
2Volume of moving object
If the semiconductor layer thickness is limited compared to the substrate thickness, then the multi-layer structure can be formed, but the electrical resistance increases and device property uniformity deteriorates
Solution Approach 1:
The patent changes the doping concentration parameter locally in the semiconductor layer by forming a well region with higher doping concentration than the substrate. This parameter change increases the electrical conductivity in the thinner semiconductor layer, compensating for the resistance increase that would otherwise result from the limited layer thickness.
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 uniformity of device properties and reduces resistance differences between substrate and layer, improving the performance and consistency of multi-layer nonvolatile memory devices.
Implementation Method 1
a well region in the first semiconductor layer having a doping concentration higher than that of a well region formed in a semiconductor substrate
Data Source
AI summary
A nonvolatile memory device includes a semiconductor substrate having a first well region of a first conductivity type, and at least one semiconductor layer formed on the semiconductor substrate. A first cell array is formed on the semiconductor substrate, and a second cell array formed on the semiconductor layer. The semiconductor layer includes a second well region of the first conductivity type having a doping concentration greater than a doping concentration of the first well region of the first conductivity type. As the doping concentration of the second well region is increased, a resistance difference may be reduced between the first and second well regions.