Fluorine Gradient Charge Storage Layer for 3D Memory Reliability
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Solution Overview
Problem
In semiconductor memory devices, such as three-dimensional memory, charge stored in the charge storage layer can leak due to shallow trap levels and high trap density, leading to inefficient charge storage characteristics.
Innovation Solution
A semiconductor device with a charge storage layer that includes a fluorine-containing region with a peak concentration gradient, where fluorine is added only to specific parts of the silicon nitride film to form deep trap levels and reduce trap density, preventing charge leakage by optimizing the distribution of fluorine concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorine is added to the charge storage layer to deepen trap levels, then charge storage characteristics improve, but trap density decreases
Solution Approach 1:
The patent applies local quality by creating a fluorine concentration gradient within the charge storage layer, where fluorine concentration varies spatially rather than being uniform. The concentration is higher near the charge storage layer-forming interface and decreases toward the block insulating film interface, allowing different regions to serve different functions: deepening trap levels near the storage interface while preserving trap density in other regions
Solution Approach 2:
The patent changes the concentration parameter of fluorine within the charge storage layer by establishing a gradient distribution. Instead of adding fluorine uniformly, the concentration is controlled to decrease from one interface to another, transforming a single-parameter (uniform concentration) approach into a multi-parameter (spatially varying concentration) solution that simultaneously achieves trap level deepening and trap density preservation
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
This approach effectively improves charge storage characteristics by deepening trap levels and limiting the decrease in trap density, thereby preventing charge leakage and enhancing the overall performance of the semiconductor memory device.
Implementation Method 1
ion implantation conditions including a fluorine ion concentration, an energy, and a temperature
Data Source
AI summary
A semiconductor memory device includes a stacked structure and a memory pillar. The stacked structure includes electrode layers and insulating layers alternately provided on a substrate. The memory pillar extends through the stacked structure in a thickness direction. The memory pillar includes a semiconductor layer extending along the thickness direction, and a first insulating film, a charge storage layer, and a second insulating film provided around the semiconductor layer. The charge storage layer contains fluorine, and a fluorine concentration in the charge storage layer has a gradient along a plane direction of the substrate with a peak. A first distance from an inner end of the charge storage layer to the peak in the plane direction is shorter than a second distance from an outer end of the charge storage layer to the peak in the plane direction.