Ferroelectric Memory Cell Layout With Asymmetric Bit Line Extension
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Solution Overview
Problem
Existing ferroelectric memory devices suffer from narrow memory windows and slower read speeds due to symmetric source and bit line structures, which limit their performance and density in integrated circuits.
Innovation Solution
The implementation of asymmetric source and bit line structures in ferroelectric FETs, where the bit line extends further than the source line, enhances the fringing electric field and widens the memory window, improving read speed and memory performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If symmetric source and bit line structures are used in ferroelectric FETs, then device simplicity is maintained, but memory window width and read speed are limited
Solution Approach 1:
The patent applies asymmetry by making the bit line extend further than the source line beyond the channel region. This asymmetric configuration creates an extended fringing electric field that widens the memory window and improves read speed, directly resolving the technical contradiction between device simplicity and memory performance.
2Productivity
If conventional ferroelectric FET structures are used, then manufacturing process simplicity is maintained, but read speed and memory performance are slower
Solution Approach 1:
The asymmetric bit line extension is integrated into existing manufacturing workflows with minimal additional complexity. The bit line is formed to extend beyond the channel region while the source line maintains conventional dimensions, creating the performance-enhancing fringing field effect without requiring fundamentally new fabrication processes.
Solution Approach 2:
The patent applies local quality by modifying only the bit line structure in the region beyond the channel, while keeping the source line and channel structures conventional. This localized modification achieves performance improvement without requiring comprehensive redesign of the entire device structure.
3Reliability
If symmetric line structures are used, then device area is minimized, but memory window remains narrow limiting density
Solution Approach 1:
The asymmetric bit line extension utilizes space beyond the channel region to create an extended fringing electric field. This approach widens the memory window and enables higher density applications while occupying minimal additional area, as the extension is confined to the region beyond the active channel.
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 asymmetric structure design results in a widened memory window and faster read speeds, enabling high-density memory applications with improved reliability and endurance.
Implementation Method 1
The asymmetric structure design results in a widened memory window and faster read speeds, enabling high-density memory applications with improved reliability and endurance
Data Source
AI summary
A semiconductor device includes a semiconductor substrate. The semiconductor device further includes a word line structure disposed over the semiconductor substrate. In some aspects, the word line structure extends along a first direction. The semiconductor device further includes a ferroelectric layer in contact with the word line structure and traversing an entirety of the word line structure. The semiconductor device further includes a channel layer electrically coupled to the word line structure and extending continuously across an array of memory cells.