Semiconductor Device Contact Part Anisotropic Etching
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Solution Overview
Problem
In the manufacturing of three-dimensionally stacked semiconductor storage devices, existing methods face challenges in ensuring proper connection and uniform doping of silicon crystal layers, leading to potential failures in memory cell formation and variations in threshold voltages of transistors.
Innovation Solution
The method involves anisotropic etching of memory holes before epitaxial growth of silicon crystals, followed by sequential doping with boron, to form contact parts with controlled boron concentration, ensuring a flat surface for semiconductor body connection and reducing threshold voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If epitaxial growth is performed directly without anisotropic etching, then the manufacturing process is simpler, but the connection between semiconductor bodies and contact parts is poor and doping uniformity is insufficient
Solution Approach 1:
Anisotropic etching is performed as a preliminary step before epitaxial growth to prepare the substrate surface. This pre-treatment creates a flat surface and removes impurities, ensuring better connection quality and doping uniformity in the subsequent epitaxial growth process.
Solution Approach 2:
The manufacturing process is divided into distinct sequential steps: anisotropic etching followed by epitaxial growth. This segmentation allows each process to be optimized independently, with etching preparing the surface and epitaxial growth forming the crystal structure with controlled doping.
2Reliability
If boron doping is not controlled sequentially, then the doping process is simpler, but threshold voltage variations increase and transistor reliability decreases
Solution Approach 1:
Boron doping is performed as a preliminary action during the epitaxial growth process. By incorporating boron doping into the epitaxial growth step, the patent ensures uniform distribution of dopant atoms throughout the crystal structure, controlling threshold voltage and improving transistor reliability.
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 connection between semiconductor bodies and contact parts, reduces transistor failure rates, and minimizes electric resistance, thereby improving the reliability and performance of memory cells.
Implementation Method 1
anisotropic etching of memory holes before epitaxial growth of silicon crystals
Implementation Method 2
epitaxial growth of silicon crystals
Implementation Method 3
sequential doping with boron, to form contact parts with controlled boron concentration
Data Source
AI summary
A semiconductor device according to an embodiment includes: a semiconductor substrate including a first surface, a first contact part provided at a deeper level than the first surface, and a second contact part protruding up to a higher level than the first surface from the first contact part; a stacked body in which insulating layers and electrode layers are alternately stacked on the first surface; and a semiconductor film extending, on the second contact part, in the stacked body in a first direction perpendicular to the first surface. At an interface between the first contact part and the second contact part, a length of the first contact part in a second direction parallel to the first surface is larger than a length of the second contact part in the second direction.