3D NAND Gate Groove Structure for Better Channel Control
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Solution Overview
Problem
The challenge of reducing transistor device size while maintaining or improving performance in 3D NAND memory devices is a critical issue, particularly due to the high demands on CMOS processes for size reduction.
Innovation Solution
A method for manufacturing semiconductor devices involves forming grooves and gates in specific configurations within the substrate, including shallow trench isolation structures and varying gate insulating layer thicknesses to enhance gate control over transistor channels, thereby increasing effective gate lengths and improving electrical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stack layers is increased to increase memory density, then memory capacity increases, but the requirements on CMOS process size reduction become increasingly high
Solution Approach 1:
The patent transitions from planar 2D transistor structures to three-dimensional structures by forming grooves that extend into the substrate and filling them with gate materials. This vertical dimension addition allows increased gate control without further lateral scaling, enabling continued memory density improvement while relaxing CMOS process size reduction requirements.
Solution Approach 2:
The gate structure is nested within the groove formed in the substrate. The gate material fills the groove completely, creating a nested configuration where the gate is embedded within the substrate structure. This nesting approach maximizes the use of available space and improves gate control over the channel region.
2Quantity of substance
If transistor device size is reduced to increase memory density, then memory capacity increases, but transistor performance deteriorates
Solution Approach 1:
By forming grooves that extend vertically into the substrate and filling them with gate materials, the invention adds a vertical dimension to the gate structure. This allows the effective gate length to be increased without increasing the lateral footprint of the transistor, thereby maintaining or improving transistor performance while achieving higher memory density through size reduction.
Solution Approach 2:
The gate insulating layer thickness is varied locally - it is thicker at the sides of the groove and thinner at the top surface. This local quality variation optimizes the electric field distribution, providing enhanced gate control over the channel while maintaining compact transistor dimensions for high memory density.
Data Source
AI summary
A semiconductor device and a method for manufacturing the same, and a NAND memory device are disclosed. The method comprises: forming a substrate that comprises a first active region and an isolation region; forming a first groove between the isolation region and the first channel region, the first groove being partially located in the isolation region, and not penetrating through the isolation region; forming a first gate insulating layer covering the first groove and the first channel region; forming a first gate on the first gate insulating layer, the first gate covering the first channel region and filling the first groove.