Semiconductor Storage Device Boron Diffusion Barrier
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Solution Overview
Problem
Existing semiconductor storage devices face challenges in effectively controlling the drain select transistor due to boron diffusion during heat treatment, leading to difficulties in turning on the transistor and maintaining suitable control over the device.
Innovation Solution
Incorporating a second portion of the semiconductor film with a higher concentration of carbon, which prevents boron diffusion and ensures proper operation of the drain select transistor by maintaining the structural integrity and impurity distribution within the semiconductor pillars.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If heat treatment is applied during manufacturing, then the semiconductor device can be formed, but boron diffusion occurs causing difficulty in turning on the drain select transistor
Solution Approach 1:
A carbon-containing layer is introduced as an intermediary between the n-type impurity region and the external environment during heat treatment. This carbon layer acts as a diffusion barrier that prevents boron from migrating into the semiconductor film, thereby protecting the transistor's electrical characteristics while allowing the heat treatment process to proceed.
Solution Approach 2:
The invention changes the chemical composition parameter of the protective layer by incorporating carbon at a concentration of 1×10^19 to 1×10^21 atoms/cm³. This specific carbon concentration range optimizes the barrier effect against boron diffusion while maintaining compatibility with the heat treatment process and transistor operation.
2Reliability
If carbon concentration is increased in the semiconductor film, then boron diffusion is prevented, but the device complexity increases
Solution Approach 1:
The carbon concentration is not uniformly distributed throughout the entire semiconductor device but is specifically localized in the n-type impurity region where boron diffusion is most problematic. This localized approach prevents boron contamination only where needed, maintaining simple device structure elsewhere while achieving effective diffusion control.
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 enhances the likelihood of turning on the drain select transistor and allows for better control of the semiconductor storage device, preventing boron diffusion and ensuring effective operation.
Implementation Method 1
a second portion of the semiconductor film farther from the substrate than the first portion and connected to the first semiconductor pillar at the second portion of the first semiconductor pillar, the second portion of the first semiconductor pillar containing carbon (C)
Data Source
AI summary
A semiconductor storage device includes a substrate, a plurality of first gate electrodes on the substrate and arranged in a thickness direction of the substrate, and a first semiconductor pillar extending in the thickness direction of the substrate through the plurality of first gate electrodes, the first semiconductor pillar including a first portion facing the plurality of first gate electrodes and a second portion farther from the substrate than the first portion. The semiconductor storage device also includes a second gate electrode on the substrate farther from the substrate than the plurality of first gate electrodes, and a second semiconductor pillar extending in the thickness direction of the substrate through the second gate electrode, and connected to the first semiconductor pillar at the second portion of the first semiconductor pillar. The second portion of the first semiconductor pillar contains carbon (C).