Germanium Source Structure for 3D NAND Storage Density
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Solution Overview
Problem
Existing semiconductor memory devices face challenges in achieving high-density and efficient memory storage due to limitations in source structure design, particularly in three-dimensional vertical NAND strings.
Innovation Solution
A memory device is developed with a germanium-containing source structure, featuring a semiconductor source line layer with silicon and electrical dopants, an alternating stack of insulating and conductive layers, a memory opening fill structure including a silicon-germanium structure, and a method for forming these components to enhance memory performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional silicon-based source structures are used in three-dimensional vertical NAND strings, then manufacturing process is simpler, but storage density and memory performance are limited
Solution Approach 1:
The patent changes the material composition parameter of the source structure by incorporating germanium into the silicon-based source line layer, forming silicon-germanium alloys with varying germanium concentrations. This parameter change enables higher storage density and improved memory performance while managing the increased structural complexity through controlled material composition gradients
Solution Approach 2:
The patent employs composite materials by creating a multi-layered source structure consisting of silicon-germanium alloy layers with different germanium concentrations, combined with barrier layers and contact layers. This composite approach allows optimization of both storage density and electrical performance while addressing the complexity through functional layer integration
2Productivity
If germanium-containing materials are introduced to enhance storage density, then memory performance improves, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the silicon-germanium source structure with appropriate barrier layers and contact layers before subsequent memory cell formation processes. This preliminary structuring enables higher storage density and efficiency while simplifying later manufacturing steps by having the complex germanium-containing structure already in place
Solution Approach 2:
The patent implements local quality by varying the germanium concentration and composition in different regions of the source structure. Specific areas have optimized germanium content for electrical performance, while other regions have different compositions for manufacturing compatibility, thereby achieving high productivity without uniformly increasing manufacturing complexity throughout the entire device
3Reliability
If silicon-germanium structures are formed to improve electrical contact, then reliability increases, but additional processing steps are required
Solution Approach 1:
The patent merges multiple functions into the silicon-germanium source structure by combining electrical contact, barrier, and doping functions into integrated layers. This merging improves electrical contact reliability by ensuring proper interfaces and material combinations, while reducing the need for separate processing steps for each function, thereby managing the overall device complexity
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 germanium-containing source structure improves memory device performance by increasing storage density and efficiency, while the silicon-germanium structure enhances electrical contact and reliability, addressing the limitations of existing technologies.
Implementation Method 1
forming a silicon-germanium structure including a silicon-germanium material by interdiffusing the germanium-containing material with a silicon-containing material in the end portion of the vertical semiconductor channel
Implementation Method 2
converting the amorphous germanium-containing semiconductor layer into a polycrystalline germanium-containing semiconductor source line layer using metal-induced crystallization by diffusing metal atoms from the metal containing layer through the amorphous germanium-containing semiconductor layer
Implementation Method 3
by diffusing metal atoms from the metal containing layer through the amorphous germanium-containing semiconductor layer
Data Source
AI summary
A memory device includes a semiconductor source line layer containing silicon and electrical dopants, an alternating stack of insulating layers and electrically conductive layers located over the semiconductor source line layer, a memory opening vertically extending through the alternating stack, and a memory opening fill structure located in the memory opening. The memory opening fill structure includes a memory film, a vertical semiconductor channel including silicon that is laterally surrounded by the memory film, and a silicon-germanium structure contacting an end portion of the vertical semiconductor channel and contacting the semiconductor source line.