Doped Semiconductor Support Structures to Prevent 3D NAND Galvanic Corrosion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During the fabrication of vertically-stacked three-dimensional NAND memory devices, unintended etching of supporting semiconductor material can lead to structural collapse and device failure due to galvanic corrosion, which occurs when metal-containing conductive material is exposed under the semiconductor material during processing.
Innovation Solution
Distributing modifying substances such as carbon and/or metal within the semiconductor material to alter its properties, preventing or alleviating galvanic corrosion by balancing the oxidation potentials of the exposed surfaces, thereby reducing or eliminating void formation and structural weakness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If metal-containing conductive material is exposed under semiconductor material during processing, then electrical conductivity is improved, but galvanic corrosion occurs causing structural collapse
Solution Approach 1:
A modifying substance (such as carbon or metal dopant) is introduced as an intermediary between the metal-containing conductive material and the semiconductor material. This intermediary layer prevents direct galvanic interaction while allowing electrical functionality to be maintained, thus resolving the contradiction between conductivity and structural integrity.
Solution Approach 2:
The oxidation potential of the semiconductor material surface is altered by doping with modifying substances (carbon or metal). This parameter change balances the oxidation potentials between adjacent materials, preventing galvanic corrosion while maintaining the exposed surface configuration needed for electrical conductivity.
2Ease of operation
If semiconductor material is etched to expose metal-containing conductive material, then access to conductive layers is improved, but void formation and structural weakness occur
Solution Approach 1:
The modifying substance is selectively distributed within the semiconductor material at locations where exposure to metal-containing conductive material is anticipated. This local modification provides targeted protection against galvanic corrosion only where needed, maintaining structural strength while allowing etching access to conductive layers.
Solution Approach 2:
The semiconductor material is pre-doped with modifying substances before etching processes that would expose metal-containing conductive material. This preliminary action ensures that when the semiconductor is later etched, the modifying substance is already in place to prevent galvanic corrosion, avoiding void formation and structural weakness.
3Reliability
If modifying substances are distributed within semiconductor material, then galvanic corrosion is prevented, but manufacturing complexity increases
Solution Approach 1:
The introduction of modifying substances is merged with existing semiconductor fabrication processes such as doping or deposition steps. By combining the corrosion protection function with routine manufacturing operations, the solution prevents galvanic corrosion without significantly increasing overall manufacturing complexity.
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 modification of semiconductor material properties with carbon and/or metal dopants effectively prevents galvanic corrosion, ensuring the structural integrity of vertically-stacked memory devices and preventing device failure by maintaining the support structure's stability during processing.
Implementation Method 1
unintended etching of supporting semiconductor material can lead to structural collapse and device failure due to galvanic corrosion, which occurs when metal-containing conductive material is exposed under the semiconductor material during processing
Implementation Method 2
Distributing modifying substances such as carbon and/or metal within the semiconductor material to alter its properties
Data Source
AI summary
Some embodiments include a method of forming an integrated assembly. A stack of alternating first and second materials is formed over a conductive structure. The conductive structure includes a semiconductor-containing material over a metal-containing material. An opening is formed to extend through the stack and through the semiconductor-containing material, to expose the metal-containing material. The semiconductor-containing material is doped with carbon and/or with one or more metals. After the doping of the semiconductor-containing material, the second material of the stack is removed to form voids. Conductive material is formed within the voids. Insulative material is formed within the opening. Some embodiments include integrated assemblies having carbon distributed within at least a portion of a semiconductor material.