3D Memory Electrode Barrier Layer for Nitrogen Diffusion Control
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Solution Overview
Problem
The challenge in forming a barrier metal layer in an electrode layer of a three-dimensional semiconductor memory, particularly when using a molybdenum layer, is the diffusion of nitrogen atoms from the barrier metal layer to the electrode material layer, leading to increased electric resistance and reduced data retention due to the diffusion of oxygen, hydrogen, and other atoms.
Innovation Solution
The use of a barrier metal layer composed of molybdenum, silicon, and nitrogen, with a MoSiN film structure, prevents the diffusion of nitrogen atoms to the electrode material layer, thereby maintaining low electric resistance and enhancing data retention by trapping hydrogen and other atoms within the barrier metal layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a molybdenum layer is used as the electrode material layer, then the electrical conductivity is improved, but nitrogen atoms diffuse from the barrier metal layer to the electrode material layer causing increased electric resistance
Solution Approach 1:
The barrier metal layer is formed as a composite structure containing multiple elements (molybdenum, silicon, nitrogen, and optionally carbon or oxygen) to create a MoSiN-based compound material. This composite composition provides superior barrier properties against nitrogen diffusion compared to simple molybdenum or molybdenum nitride layers, resolving the contradiction between maintaining electrical conductivity and preventing nitrogen atom diffusion.
2Reliability
If the barrier metal layer composition is optimized to prevent nitrogen diffusion, then data retention is improved, but the complexity of layer formation increases
Solution Approach 1:
The barrier metal layer composition is precisely controlled within specific parameter ranges: nitrogen content at 20-80 at%, silicon content at 5-80 at%, and optional carbon at 1-20 at% or oxygen at 1-20 at%. By defining these compositional parameters, the patent achieves effective nitrogen diffusion prevention while managing the complexity through quantifiable composition specifications rather than vague material descriptions.
Solution Approach 2:
The use of MoSiN composite material with specific stoichiometric ratios simplifies the formation process compared to multi-layer structures. The composite nature allows single-step deposition methods to achieve the desired barrier properties, reducing process complexity while maintaining effectiveness in preventing nitrogen diffusion.
3Ease of manufacture
If a conventional barrier metal layer is used, then the manufacturing process is simple, but oxygen and hydrogen atoms diffuse causing reduced data retention
Solution Approach 1:
The MoSiN-based composite barrier metal layer with specific composition ratios provides enhanced barrier properties against multiple types of atomic diffusion (nitrogen, oxygen, and hydrogen) simultaneously. This single composite layer replaces what would otherwise require multiple different barrier layers, maintaining ease of manufacture through a streamlined process while improving reliability against various diffusion mechanisms.
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 configuration suppresses the increase in electric resistance and maintains data retention by preventing the diffusion of nitrogen, oxygen, and hydrogen atoms, ensuring stable performance of the semiconductor device.
Implementation Method 1
a barrier metal layer composed of molybdenum, silicon, and nitrogen, with a MoSiN film structure, prevents the diffusion of nitrogen atoms to the electrode material layer
Implementation Method 2
enhancing data retention by trapping hydrogen and other atoms within the barrier metal layer
Data Source
AI summary
In one embodiment, a semiconductor device includes a stacked film including a plurality of electrode layers and a plurality of first insulators that are alternately provided in a first direction. The device further includes a columnar portion extending in the first direction in the stacked film, and including a charge storage layer provided on a side face of the stacked film via a second insulator, and a semiconductor layer provided on a side face of the charge storage layer via a third insulator. A first electrode layer among the plurality of electrode layers includes a first layer including molybdenum, nitrogen, and a Group 14 element, and a second layer including molybdenum.