U-Shaped NAND Channel Crystallization via Metal Gettering
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Solution Overview
Problem
Existing methods face challenges in reproducibly forming desired crystalline textures within U-shaped NAND channel materials in flash memory configurations, which affects the performance and reliability of NAND memory devices.
Innovation Solution
The use of metal-induced crystallization (MIC) and metal-induced lateral crystallization (MILC) processes, where metal is introduced adjacent to one end of a semiconductor channel material and thermally processed to induce crystallization, with gettering regions to trap and remove the metal, resulting in semiconductor channel materials with grain boundaries parallel to the gate dielectric surfaces, thereby achieving the desired crystalline texture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to form channel material in U-shaped NAND configuration, then the basic structure can be created, but the desired crystalline texture cannot be reproducibly formed
Solution Approach 1:
Gettering regions are formed in advance at specific locations (such as at the ends of the U-shaped channel material or in the corner regions) before the channel material formation process. These pre-positioned gettering regions are designed to automatically attract and trap metal during subsequent processing steps, ensuring that metal accumulates in predetermined locations rather than randomly distributed throughout the channel material, thereby achieving reproducible crystalline texture formation.
Solution Approach 2:
Gettering regions serve as intermediary structures that mediate between the channel material formation process and metal contamination control. These regions act as sacrificial elements that intentionally attract metal away from the channel material, using the metal's natural affinity for certain materials to achieve the desired crystalline texture without direct intervention in the channel material formation itself.
2Manufacturing precision
If metal is introduced to induce crystallization, then desired crystalline texture is achieved, but metal contamination in channel material increases
Solution Approach 1:
Gettering regions are strategically positioned to extract and trap metal from the channel material after the metal-induced crystallization process. By placing gettering regions at specific locations such as the ends of the U-shaped structure or in corner regions, the metal is pulled out from the channel material and concentrated in the gettering regions, thereby reducing metal contamination in the functional channel material while preserving the desired crystalline texture.
Solution Approach 2:
The metal that would otherwise be a harmful contaminant is converted into a beneficial tool for inducing crystallization. The process intentionally introduces metal to achieve the desired crystalline texture, then uses gettering regions to control and relocate the metal to acceptable locations. This transforms the harmful aspect of metal contamination into a controlled process step that achieves both crystallization and contamination management.
3Object-affected harmful factors
If gettering regions are added to trap metal, then metal concentration is reduced, but device structure becomes more complex
Solution Approach 1:
The gettering structure is segmented into specific functional regions within the existing device architecture. Rather than adding a completely separate gettering system, the gettering regions are integrated as specific zones (such as end regions or corner regions of the U-shaped structure) that perform the metal-trapping function. This segmentation allows the gettering function to be distributed throughout the existing structure, minimizing additional complexity while achieving effective metal control.
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 allows for the formation of semiconductor channel materials with aligned grain boundaries, improving the Ion/Ioff characteristics of NAND memory devices and ensuring a metal concentration of less than 0.5 atomic percent, comparable to devices without metal, enhancing the reliability and performance of NAND flash memory.
Implementation Method 1
The metal induces crystallization of the semiconductor material to transition the first crystallographic texture to a second crystallographic texture
Implementation Method 2
The metal and the semiconductor material are thermally processed
Implementation Method 3
Thermodynamics may drive the metal along the semiconductor material from the first end to the second end, and then from the semiconductor material into the first gettering region, and then from the first gettering region to the second gettering region
Data Source
AI summary
Some embodiments include an integrated structure having semiconductor material within a region between two parallel surfaces. The semiconductor material has grain boundaries parallel to the parallel surfaces. At least one circuit component utilizes a region of the semiconductor material in a gated device. The semiconductor material has little if any metal therein so that the gated device has Ion/Ioff characteristics similar to if the semiconductor material had no metal therein. Some embodiments include a method in which semiconductor material is provided between a pair of parallel surfaces, and in which the parallel surfaces and semiconductor material extend between a first end and a second end. Metal is formed adjacent the first end, and gettering material is formed adjacent the second end. Thermal processing induces crystallization of the semiconductor material and drives the metal along the semiconductor material and into the gettering material. The gettering material is then removed.