Hydrogen Supply Film and Barrier Layout for Memory Cell Passivation
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Solution Overview
Problem
In semiconductor memory devices, high temperature annealing in the back-end-of-line (BEOL) for hydrogenation can lead to leakage currents in transistors and compensation capacitors, affecting chip reliability and memory cell performance, while simultaneously failing to effectively saturate dangling bonds in memory cell interfaces, thus necessitating a method to provide hydrogen to memory cells while controlling excess hydrogen around compensation capacitors.
Innovation Solution
Incorporating a hydrogen supply film that releases hydrogen or hydrogen ions during thermal processes, combined with a hydrogen barrier film to prevent hydrogen migration to sensitive areas, such as the capacitor in the back-end-of-line, allowing for effective hydrogenation of memory cells without affecting front-end-of-line (FEOL) transistors or compensation capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature annealing in H2-N2 ambient is performed in the BEOL to supply hydrogen to memory cell interfaces, then dangling bonds in amorphous silicon are saturated and leakage currents are reduced, but leakage currents increase in FEOL transistors and compensation capacitors due to excess hydrogen
Solution Approach 1:
The patent divides the memory device into distinct regions with different hydrogen management strategies: the FEOL region receives hydrogen supply through dedicated supply films, while the BEOL region uses barrier films to prevent hydrogen ingress. This segmentation allows selective hydrogenation of memory cell interfaces without exposing FEOL components to excess hydrogen.
Solution Approach 2:
The patent introduces hydrogen barrier films as intermediary structures between the hydrogenation process and sensitive FEOL components. These barrier films act as mediators that block hydrogen diffusion pathways, preventing hydrogen from reaching FEOL transistors and capacitors while still allowing hydrogen to reach memory cell interfaces through controlled pathways.
2Quantity of substance
If high temperature annealing is performed to supply hydrogen, then hydrogenation of interfaces is effective, but characteristics of FEOL transistors are degraded
Solution Approach 1:
The patent implements local quality by creating spatially varying hydrogen concentrations through strategically placed supply and barrier films. Memory cell interfaces receive high hydrogen concentrations for effective passivation, while FEOL regions maintain low hydrogen concentrations to preserve transistor characteristics. This localized control allows different regions to have optimized hydrogen exposure levels.
Solution Approach 2:
The patent applies preliminary action by forming hydrogen barrier films in the BEOL before the hydrogenation annealing process. This pre-positioning of barrier structures ensures that when high temperature annealing is performed, hydrogen is automatically directed away from FEOL components, preventing degradation before it occurs.
3Reliability
If hydrogen is supplied to memory cells, then data reliability and refresh rates are improved, but leakage currents increase in compensation capacitors due to chemical reduction of high-k material
Solution Approach 1:
The patent introduces hydrogen barrier films as intermediary structures between the hydrogenation process and sensitive FEOL components. These barrier films act as mediators that block hydrogen diffusion pathways, preventing hydrogen from reaching FEOL transistors and capacitors while still allowing hydrogen to reach memory cell interfaces through controlled pathways.
Solution Approach 2:
The patent implements local quality by creating spatially varying hydrogen concentrations through strategically placed supply and barrier films. Memory cell interfaces receive high hydrogen concentrations for effective passivation, while FEOL regions maintain low hydrogen concentrations to preserve transistor characteristics.
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 data reliability and refresh rates of memory cells by reducing leakage currents while maintaining the integrity of transistors and capacitors, thereby improving overall memory device performance.
Implementation Method 1
a hydrogen supply film that releases hydrogen or hydrogen ions during thermal processes
Implementation Method 2
a hydrogen barrier film to prevent hydrogen migration to sensitive areas
Implementation Method 3
Supplying hydrogen to the interfaces of the memory cells may deactivate the defects by saturating dangling bonds of amorphous silicon
Data Source
AI summary
Apparatuses and methods for controlling hydrogen supply in manufacturing memory devices are described. An example apparatus includes: a first capacitor disposed above a substrate; a hydrogen supply film above the first capacitor; a second capacitor above the hydrogen supply film; and a barrier film between the hydrogen supply film and the second capacitor. The hydrogen supply film provides hydrogen and/or hydrogen ions. The barrier film is hydrogen-impermeable.