Vertical-Channel Semiconductor Device With Buried Bit Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As the degree of integration in semiconductor devices increases, the reduced channel length leads to increased parasitic capacitance and the floating body effect, degrading device characteristics.
Innovation Solution
A vertical-channel semiconductor device is designed with a body-tied structure and buried bit lines, where active pillars are isolated from the substrate by insulation films, and air gaps are formed to reduce parasitic capacitance and prevent the floating body effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the channel length is reduced to increase integration degree, then the device size is reduced, but parasitic capacitance increases and characteristics deteriorate
Solution Approach 1:
The patent transitions from planar channel structure to vertical channel structure, changing the dimensional orientation of the channel from horizontal to vertical. This allows the channel length to extend in the vertical direction while maintaining a compact horizontal footprint, thereby reducing device area while avoiding excessive parasitic capacitance that would result from horizontal scaling.
Solution Approach 2:
The active region is segmented into multiple isolated active pillars separated by insulation films. This segmentation creates discrete vertical channels that are electrically isolated from each other, allowing independent control and reducing parasitic interactions between adjacent channels while maintaining high integration density.
2Reliability
If active pillars are isolated from substrate by insulation films, then parasitic capacitance is reduced, but floating body effect occurs
Solution Approach 1:
A body-tied structure is introduced as an intermediary element that electrically connects the active pillars to the substrate. This mediator provides a path for minority carriers to be collected, preventing charge accumulation in the isolated active pillars and eliminating the floating body effect while maintaining the electrical isolation benefits of the insulation films.
3Reliability
If buried bit lines are disposed below gates, then parasitic capacitance between bit lines is reduced, but device complexity increases
Solution Approach 1:
The bit line is repositioned from a lateral configuration to a buried vertical configuration below the gates. This dimensional change allows the bit line to be disposed in the vertical direction, increasing the distance between bit lines and reducing parasitic capacitance while integrating the bit line formation into the existing vertical processing steps.
Data Source
AI summary
A vertical-channel semiconductor device having a buried bit line is disclosed. The vertical-channel semiconductor device enables an active pillar including a vertical channel region to be separate from a substrate, couples the active pillar to the substrate using a body-tied structure, and prevents a floating body effect from occurring therein. In addition, the vertical-channel semiconductor device includes an air gap between buried bit lines to reduce parasitic capacitance between the bit lines.