SiON Insulating Film N/O Ratio Control for Memory Reliability
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Solution Overview
Problem
Current semiconductor memory devices with cross-point structures using phase-change memory (PCM) face challenges in maintaining enhanced electrical properties and preventing water and oxygen ingress, which can lead to performance degradation and RC delay.
Innovation Solution
The semiconductor memory device incorporates a SiON insulating film with varying atomic ratios of nitrogen (N) to oxygen (O) along the interconnects and storage layers, preventing water and oxygen ingress and enhancing pressure resistance and electrical properties by controlling the N/O ratio in specific positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional insulating film is used in the cross-point structure, then the device structure is simple, but water and oxygen ingress occurs leading to performance degradation and increased RC delay
Solution Approach 1:
The insulating film is designed with spatially varying nitrogen concentration, creating regions with different protective properties. The nitrogen concentration is higher at specific locations (such as near the storage layer or interconnect interfaces) where water and oxygen ingress is most problematic, while maintaining lower nitrogen concentration in other regions to preserve electrical performance and maintain manufacturing feasibility.
Solution Approach 2:
The insulating film is constructed as a composite material system combining silicon oxide base material with nitrogen doping. This creates a multi-functional film that provides both the fundamental insulating properties of silicon oxide and the enhanced water/oxygen barrier properties contributed by nitrogen, achieving superior protection without requiring completely separate barrier layers.
2Object-affected harmful factors
If the nitrogen concentration is increased throughout the insulating film, then water and oxygen resistance improves, but electrical properties and manufacturing feasibility deteriorate
Solution Approach 1:
The insulating film is designed with spatially varying nitrogen concentration, creating regions with different protective properties. The nitrogen concentration is higher at specific locations (such as near the storage layer or interconnect interfaces) where water and oxygen ingress is most problematic, while maintaining lower nitrogen concentration in other regions to preserve electrical performance and maintain manufacturing feasibility.
Solution Approach 2:
The nitrogen concentration parameter is varied continuously or discontinuously throughout the insulating film structure. By controlling the nitrogen concentration profile (rather than using a uniform concentration), the film achieves optimal balance between water/oxygen resistance and electrical properties, as the nitrogen is strategically placed only where barrier functionality is most needed.
3Ease of manufacture
If a uniform nitrogen concentration is used in the insulating film, then manufacturing is simplified, but targeted protection against water and oxygen ingress is insufficient
Solution Approach 1:
The insulating film is designed with spatially varying nitrogen concentration, creating regions with different protective properties. The nitrogen concentration is higher at specific locations (such as near the storage layer or interconnect interfaces) where water and oxygen ingress is most problematic, while maintaining lower nitrogen concentration in other regions to preserve electrical performance and maintain manufacturing feasibility.
Solution Approach 2:
The nitrogen doping is incorporated during the insulating film formation process itself, rather than requiring subsequent separate doping steps. This preliminary incorporation of nitrogen at specific locations within the film structure achieves targeted protection while maintaining manufacturing simplicity, as the nitrogen is introduced in-situ during deposition through controlled doping conditions.
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 effectively prevents water and oxygen from entering the storage layer, maintaining low resistance states and improving pressure resistance, thereby enhancing the overall electrical performance and stability of the memory device.
Implementation Method 1
The atomic ratio (N/O) between N and O in the first insulating film is not less than 1.0 at a first position which is the position of the second interconnect-side end surface of the first storage layer in the third direction
Data Source
AI summary
A semiconductor memory device includes a first interconnect, a second interconnect, a first storage layer, and a first insulating film. The first insulating film is provided along a surface of a part of the second interconnect and a surface of the first storage layer. The first insulating film is composed of Si, N, and O. The atomic ratio (N/O) between N and O in the first insulating film is not less than 1.0 at a first position which is the position of the second interconnect-side end surface of the first storage layer in a third direction. The atomic ratio (N/O) between N and O in the first insulating film is less than 1.0 at a second position which is the position of the end surface of the second interconnect, opposite to the first storage layer-side end surface, in the third direction.