Vertical Memory Cell Pillars With Out-Diffused Select-Device Doping
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Solution Overview
Problem
Existing methods struggle to achieve desired heavily-doped regions in channel material pillars for vertically-stacked memory cells, which are crucial for improving memory devices.
Innovation Solution
A method involving the formation of conductively-doped semiconductor material within channel material pillars, followed by out-diffusion of dopant to create heavily-doped regions, is employed to enhance the characteristics of select devices in memory cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doping methods are used to form doped regions in channel material pillars, then the doping process is simpler, but the desired heavily-doped regions cannot be achieved with sufficient doping levels
Solution Approach 1:
The patent applies preliminary action by forming conductively-doped semiconductor material within the channel material pillars before the actual doping process. This pre-formed doped material serves as a dopant source that will subsequently out-diffuse into the channel material, ensuring sufficient doping levels are achieved without requiring complex conventional doping processes. The conductively-doped semiconductor material is formed in advance to prepare the structure for effective dopant out-diffusion.
2Reliability
If higher doping levels are achieved in channel material pillars, then select device performance is improved, but the risk of creating harmful leakage currents increases
Solution Approach 1:
The patent applies local quality by creating spatially varying doping concentrations within the channel material pillars. The dopant out-diffusion from the conductively-doped semiconductor material creates a non-uniform doping profile where heavily-doped regions are formed at specific locations (such as near the select device channels) while other regions maintain lower doping levels. This localized heavy doping improves select device performance where needed while avoiding excessive doping in regions where it would cause harmful leakage currents.
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 select devices with desired doping levels, balancing non-leaky 'OFF' and leaky GIDL characteristics, thereby enhancing the performance of memory devices.
Implementation Method 1
Dopant is out-diffused from the conductively-doped second semiconductor material into the first semiconductor material
Data Source
AI summary
Some embodiments include a method in which a first stack is formed to include a metal-containing first layer, a second layer over the first layer, and a metal-containing third layer over the second layer. A first opening is formed to extend through the second and third layers. A sacrificial material is formed within the first opening. A second stack is formed over the first stack. A second opening is formed through the second stack, and is extended through the sacrificial material. First semiconductor material is formed within the second opening. A third opening is formed through the second stack and to the second layer. The second layer is removed to form a conduit. Conductively-doped second semiconductor material is formed within the conduit. Dopant is out-diffused from the conductively-doped second semiconductor material into the first semiconductor material. Some embodiments include integrated assemblies.