3D Memory Channel Contact Structure for Stable Polarization Switching
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Solution Overview
Problem
High doping of the channel layer in 3D memory devices leads to negative transition voltage, while low resistance can cause reading failures due to reduced electric field across the channel layer, inhibiting polarization switching and memory state transitions.
Innovation Solution
Incorporating a contact structure with lower resistance than the channel layer to form ohmic contacts between the source and drain, and using gate extension structures to enhance the electric field across the channel layer, facilitating polarization switching and maintaining positive transition voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high doping is applied to the channel layer to reduce contact resistance, then contact resistance decreases, but transition voltage becomes negative causing reading failures
Solution Approach 1:
The invention segments the channel layer into two distinct regions: a first channel layer portion with higher doping concentration to reduce contact resistance, and a second channel layer portion with lower doping concentration to maintain positive transition voltage and enable proper reading operation. This spatial segmentation allows each region to optimize for its specific function without compromising the other.
Solution Approach 2:
The invention applies local quality by assigning different doping concentrations to different spatial locations within the channel layer. The first portion near the contact structures receives high doping for low resistance, while the second portion in the active channel region maintains low doping for proper voltage characteristics, ensuring each location has the optimal property for its intended function.
2Reliability
If low resistance is used in the channel layer to improve conductivity, then electrical conductivity increases, but electric field strength decreases inhibiting polarization switching
Solution Approach 1:
The channel layer is segmented into a first portion with high doping for conductivity and a second portion with low doping for strong electric field. This segmentation enables the device to achieve both good electrical conductivity in the contact region and strong polarization switching in the active channel region.
Solution Approach 2:
Different regions of the channel layer are assigned different electrical properties: the first portion has high carrier concentration for low resistance, while the second portion has low carrier concentration for high electric field strength, allowing each region to perform its intended function optimally.
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 solution reduces contact resistance and maintains positive transition voltage, improving memory device performance by enhancing polarization switching and reducing reading failures.
Implementation Method 1
Incorporating a contact structure with lower resistance than the channel layer to form ohmic contacts between the source and drain
Implementation Method 2
using gate extension structures to enhance the electric field across the channel layer, facilitating polarization switching
Data Source
AI summary
A semiconductor device comprising a source, and a drain spaced apart from the source in a first direction. A channel layer is disposed radially outwards of at least one radially outer surface of the source and the drain in a second direction perpendicular to the first direction, the channel layer extending in the first direction. A memory layer is disposed on a radially outer surface of the channel layer in the second direction and extending in the first direction. A contact structure is interposed between the channel layer and at least a portion of the source and/or the drain, the contact structure having a lower resistance than the channel layer.