Silicon Nitride Intermediate Films in 3D Memory Stacks

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Solution Overview

Problem

In three-dimensional memory devices with stacked metal and silicon oxide films, the resistance of oxidized metal films increases, leading to performance issues due to oxygen diffusion and metal contamination, which affects the insulative properties and reliability of the device.

Innovation Solution

Incorporating silicon nitride intermediate films between the metal and silicon oxide films, with higher nitrogen composition ratios at the metal interfaces and higher silicon composition ratios at the silicon oxide interfaces, to enhance adhesion, prevent oxygen diffusion, and suppress metal contamination, thereby reducing resistance and maintaining insulative properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal films are stacked alternately with silicon oxide films to form a three-dimensional memory device, then the device structure is formed, but the resistance of oxidized metal films increases due to oxygen diffusion

Engineering Contradiction:

Improvedevice performanceVSAvoidoxygen diffusion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A silicon nitride film is introduced as an intermediate layer between the metal film and silicon oxide film. This intermediary layer prevents oxygen diffusion from the silicon oxide film to the metal film, thereby preventing resistance increase in the metal electrode while maintaining the stacked structure functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses a composite structure combining silicon nitride and silicon oxide films. The silicon nitride film provides oxygen barrier properties while the silicon oxide film provides insulative properties, creating a multi-functional composite material system that solves both protection and insulation requirements.

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If metal films are stacked alternately with silicon oxide films, then the stacked structure is formed, but metal contamination occurs affecting insulative properties

Engineering Contradiction:

Improveinsulative propertiesVSAvoidmetal contamination

Core Design Contradiction:

Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The silicon nitride film serves as a barrier layer that prevents metal atoms from diffusing into the silicon oxide film. This intermediary structure maintains the compositional stability and insulative properties of the silicon oxide film by blocking metal contamination pathways.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If intermediate films are added between metal and silicon oxide films, then adhesion and protection are improved, but device structure complexity increases

Engineering Contradiction:

Improveadhesion and protectionVSAvoidstacked structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The silicon nitride film is strategically placed only at the interface between metal and silicon oxide films where oxygen diffusion and metal contamination occur. This localized approach provides protection and adhesion enhancement precisely where needed, rather than complicating the entire structure uniformly.

Inventive Principle:

Principle #3Local quality

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

The silicon nitride intermediate films effectively reduce the increased resistance of oxidized metal films, improve adhesion, and prevent metal contamination, ensuring stable and reliable performance of the three-dimensional memory device.

Implementation Method 1

The intermediate films contact the metal films and the silicon oxide films. The intermediate films contain silicon nitride. Nitrogen composition ratios of the intermediate films are higher on sides of interfaces between the intermediate films and the metal films than on sides of interfaces between the intermediate films and the silicon oxide films.

Methodology Applied

Scientific EffectDiffusion barrier: Diffusion Barrier

Implementation Method 2

The intermediate films contain silicon nitride. Nitrogen composition ratios of the intermediate films are higher on sides of interfaces between the intermediate films and the metal films than on sides of interfaces between the intermediate films and the silicon oxide films. Silicon composition ratios of the intermediate films are higher on sides of interfaces between the intermediate films and the silicon oxide films than on sides of interfaces between the intermediate films and the metal films.

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS9905462B2Semiconductor device and method for manufacturing the same

Publication Date: 2018.02.27 KIOXIA CORP

AI summary

According to one embodiment, the stacked body includes a plurality of metal films, a plurality of silicon oxide films, and a plurality of intermediate films. The intermediate films are provided between the metal films and the silicon oxide films. The intermediate films contain silicon nitride. Nitrogen composition ratios of the intermediate films are higher on sides of interfaces between the intermediate films and the metal films than on sides of interfaces between the intermediate films and the silicon oxide films. Silicon composition ratios of the intermediate films are higher on sides of interfaces between the intermediate films and the silicon oxide films than on sides of interfaces between the intermediate films and the metal films.