Word Line Trench Structure for Wider Gate Channels in Semiconductor Memory
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor structures with small channel widths result in high resistance and low current between the source and drain, limiting device performance, and increasing the active area width to address this issue can lead to short-circuits between adjacent areas.
Innovation Solution
A semiconductor structure is manufactured with a second protruding structure at the bottom of the word line trench, where the lower portion is narrower than the upper portion, increasing the channel width of the gate without expanding the active area width, thereby reducing resistance and enhancing current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the channel width of the gate is increased to reduce resistance and increase current, then the device performance is improved, but the active area width must be increased which may cause short-circuits between adjacent active areas
Solution Approach 1:
The patent applies asymmetry by creating a protruding structure with different widths at its upper and lower portions. The lower portion has a greater width than the upper portion, forming an asymmetric geometry that increases the channel width at the gate level while keeping the upper active area width constrained. This asymmetric design allows the channel to be wider where needed (at the gate) without expanding the overall active area footprint that could cause short-circuits between adjacent areas.
Solution Approach 2:
The patent utilizes vertical dimensioning by creating a protruding structure that extends upward from the substrate. By manipulating the width in the vertical cross-section (creating different widths at different heights), the invention increases the channel width without increasing the horizontal active area width. This dimensional approach allows the channel to be wider at lower levels while maintaining constrained upper width, effectively solving the contradiction between channel width and active area width.
2Reliability
If the channel width of the gate is increased to reduce resistance between source and drain, then the current flow is improved, but the active area width must be increased which reduces the distance between adjacent active areas
Solution Approach 1:
The asymmetric protruding structure allows the channel width to be increased at the gate level (improving current flow) while the upper portion width remains constrained (maintaining distance between adjacent active areas). The asymmetric geometry creates a wider lower section for better current flow and a narrower upper section for maintaining proper spacing between adjacent devices.
Solution Approach 2:
By utilizing the vertical dimension to create a protruding structure with varying width at different heights, the patent increases the channel width (improving current flow) without increasing the horizontal active area width (maintaining distance between adjacent active areas). The dimensional change allows the channel to be wider where it matters for current flow while keeping the overall footprint compact.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
This application relates to a semiconductor structure and a method for manufacturing the same, the method includes: a substrate is provided, and Shallow Trench Isolation (STI) structures are formed in the substrate, the STI structures isolating a plurality of Active Areas (AAs) spaced in the substrate; word line trenches are formed in the substrate, a depth of a portion of the word line trench in the AA being smaller than a depth of a portion in the STI structure such that a first protruding structure is formed at a bottom of the portion of the word line trench in the AA; an etch protection layer is formed on a surface of the first protruding structure; the STI structure is partially removed to form a second protruding structure based on the first protruding structure, an upper-portion sidewall and top of the second protruding structure being covered with the etch protection layer, and a lower portion of the second protruding structure being exposed from a removed portion of the STI structure; the lower portion of the second protruding structure is etched to make a width of the lower portion of the second protruding structure smaller than a width of an upper portion of the second protruding structure; and a word line structure is formed in the word line trench.