Semiconductor Diffusion Barrier for DRAM Cell Density
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Solution Overview
Problem
The challenge in dynamic random access memory (DRAM) devices is the difficulty in fabricating more memory cells on a practical-sized device without decreasing the cell area, leading to insufficient capacitance and increased refresh cycle times, which affects signal-to-noise ratio and device performance.
Innovation Solution
A semiconductor structure is developed with a diffusion barrier region containing doping atoms like carbon, nitrogen, germanium, oxygen, or xenon, formed between the contact plug and the source/drain region, preventing phosphorus diffusion from the contact plug and maintaining electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cell area is decreased to fit more memory cells on a practical-sized device, then the quantity of memory cells increases, but the capacitance becomes insufficient and refresh cycle time increases
Solution Approach 1:
The patent transitions from planar capacitor structures to vertically extended stacked capacitors that rise above the transistor level. This three-dimensional configuration increases the capacitor surface area and volume within the same footprint, thereby maintaining sufficient capacitance even as cell area decreases to accommodate higher memory cell density.
Solution Approach 2:
The stacked capacitor structure nests the capacitor vertically over the transistor, with the capacitor extending upward from the transistor region. This nesting approach allows both the transistor and capacitor to occupy overlapping horizontal space, effectively doubling the use of the cell area and maintaining capacitance requirements while reducing overall cell footprint.
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 solution enhances the yield and quality of DRAM structures by maintaining electrical integrity and improving capacitance, thereby addressing the limitations of reduced cell area and refresh cycle times.
Implementation Method 1
a diffusion barrier region, disposed at the top of the source/drain region, the diffusion barrier region comprises a plurality of doping atoms selected from the group consisting of carbon atoms, nitrogen atoms, germanium atoms, oxygen atoms, helium atoms and xenon atoms
Data Source
AI summary
The present invention provides a semiconductor structure, the semiconductor structure includes a substrate, at least one active area is defined on the substrate, a buried word line is disposed in the substrate, a source/drain region disposed beside the buried word line, a diffusion barrier region, disposed at the top of the source/drain region, the diffusion barrier region comprises a plurality of doping atoms selected from the group consisting of carbon atoms, nitrogen atoms, germanium atoms, oxygen atoms, helium atoms and xenon atoms, a dielectric layer disposed on the substrate, and a contact structure disposed in the dielectric layer, and electrically connected to the source/drain region.