Semiconductor Contact Structure With Ozone Oxide Dopant Barrier
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Solution Overview
Problem
Existing methods for forming contact structures in semiconductor devices face challenges in achieving low electrical resistance while preventing dopant migration and void formation, which are exacerbated by excessive or insufficient doping of conductive impurities.
Innovation Solution
A method involving the transformation of a silicon-containing conductive layer into an oxide layer under an ozone environment, followed by the formation of a nitride layer, which is then selectively removed to create a conductive structure with controlled dopant concentration and reduced electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If too much doped conductive impurity is used in the contact structure, then the electrical resistance decreases, but the roughness of the contact structure increases and voids are generated, which increases the electrical resistance
Solution Approach 1:
An oxide layer is formed on the surface of the silicon-containing conductive layer before the contact structure formation process. This preliminary oxidation creates a protective barrier that prevents dopant diffusion and maintains surface quality, allowing subsequent doping to achieve low resistance without the harmful effects of excessive dopant concentration
2Manufacturing precision
If the conductive impurity doped in the contact structure is decreased, then the roughness and void formation are reduced, but the electrical resistance becomes unacceptably high
Solution Approach 1:
The oxide layer serves as an intermediary between the silicon-containing conductive layer and the external environment. It acts as a diffusion barrier that controls dopant movement, enabling the contact structure to achieve optimal dopant concentration for low resistance while preventing the dopant escape that would otherwise require even higher initial doping levels
3Reliability
If conductive impurity diffuses outside the contact structure during formation, then the electrical resistance increases, but preventing this diffusion requires reducing the dopant concentration which also increases resistance
Solution Approach 1:
The oxide layer, which could be seen as an additional processing step increasing complexity, actually simplifies the overall dopant control by providing a natural diffusion barrier. This converts the potential harm of dopant diffusion into a beneficial containment mechanism, allowing higher dopant concentrations to be used effectively without loss
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 method results in a semiconductor structure with improved low electrical resistance and controlled dopant distribution, effectively preventing dopant migration and void formation, suitable for use in memory devices like dynamic random-access memory.
Implementation Method 1
A first portion of the silicon-containing conductive layer is transformed into an oxide layer under an ozone environment
Data Source
AI summary
The present disclosure provides a method of forming a semiconductor structure. The method includes the following operations. A silicon-containing conductive layer is formed between bitline structures. A first portion of the silicon-containing conductive layer is transformed into an oxide layer under an ozone environment. A nitride layer is formed on the oxide layer and the bitline structures. A portion of the nitride layer on the oxide layer and a portion of the oxide layer disposed below the portion of the nitride layer are removed. A conductive layer is formed on a second portion of the silicon-containing conductive layer after removing the portion of the oxide layer.