Tunneling Layer Nitrogen Control in 3D Memory
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Solution Overview
Problem
Conventional 3D memory device fabrication techniques face challenges in adjusting the nitrogen weight percent in tunneling layers, limiting the process window and resulting in defects and suboptimal film quality.
Innovation Solution
An annealing process is performed before semiconductor layer deposition to adjust the nitrogen weight percent in the tunneling layer, using an atmosphere with oxygen and hydrogen chloride gases to reduce nitrogen content to between 10% and 28%, improving film quality and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deposition techniques are used to form the tunneling layer, then the nitrogen weight percent can be controlled, but the process window is limited and defects occur
Solution Approach 1:
The patent applies parameter changes by performing a thermal treatment process that modifies the nitrogen weight percent in the tunneling layer after deposition. The thermal treatment uses controlled temperature and atmospheric conditions (oxygen and hydrogen chloride gases) to adjust the nitrogen content from conventional higher levels down to 28% or less, thereby expanding the achievable process window and improving film quality without requiring precise control during the deposition step alone.
2Ease of manufacture
If nitrogen weight percent in the tunneling layer is not controlled, then deposition is simpler, but defects and suboptimal film quality result
Solution Approach 1:
The patent applies preliminary action by performing the thermal treatment process before the semiconductor layer deposition. This preliminary thermal treatment adjusts the nitrogen weight percent in the tunneling layer to the desired level (28% or less) in advance, ensuring optimal film quality and electrical properties are achieved before subsequent processing steps, thereby maintaining ease of manufacture while achieving precise nitrogen control.
3Productivity
If the nitrogen weight percent in the tunneling layer is high, then the deposition process is more robust, but the electrical properties and data retention are suboptimal
Solution Approach 1:
The patent applies the taking out principle by using thermal treatment to extract excess nitrogen from the tunneling layer after deposition. The thermal treatment process in an oxygen and hydrogen chloride atmosphere removes nitrogen atoms from the tunneling layer, reducing the nitrogen weight percent from higher conventional levels down to 28% or less, thereby improving electrical properties and data retention while maintaining deposition robustness.
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 annealing process enlarges the process window for nitrogen weight percent control, reduces defects, and enhances the electrical properties and data retention of 3D memory devices by achieving a more uniform nitrogen distribution in the tunneling layer.
Implementation Method 1
An annealing process is performed before semiconductor layer deposition to adjust the nitrogen weight percent in the tunneling layer
Implementation Method 2
using an atmosphere with oxygen and hydrogen chloride gases to reduce nitrogen content
Data Source
AI summary
Embodiments of memory devices and fabrication methods thereof are disclosed. In an example, a memory device includes a substrate, a memory stack, and a channel structure. The memory stack includes interleaved conductor layers and dielectric layers over the substrate. The channel structure extends through the memory stack into the substrate and includes a functional layer that includes a tunneling layer of which a nitrogen weight percent is not greater than about 28%.