Selector Layer Doping for Uniform Memory Cell Performance
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving uniform dopant profiles in selector layers, leading to cell-to-cell variation and increased manufacturing costs due to non-uniform dopant distribution, which affects the efficiency and reliability of memory cells.
Innovation Solution
A method is employed to form a doped selector layer with a uniform dopant profile using a single patterning process, involving tilted ion implantations in opposite directions to create a uniform dopant distribution both parallel and perpendicular to the layer surface, thereby improving cell-to-cell consistency and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional doping methods are used to form selector layers, then manufacturing process is simpler, but dopant profile becomes non-uniform leading to cell-to-cell variation
Solution Approach 1:
The doping process is segmented into multiple ion implantation steps with different tilt angles (e.g., 0°, 45°, 90°) to achieve uniform dopant distribution. Each implantation step targets specific regions, and the combination of all steps produces the desired uniform profile throughout the selector layer volume.
Solution Approach 2:
The patent introduces tilt angles as an additional dimension to the conventional vertical ion implantation process. By doping at multiple tilt angles relative to the substrate normal, the method achieves three-dimensional uniform dopant distribution that cannot be obtained with single-direction implantation alone.
2Manufacturing precision
If multiple patterning processes are used to achieve uniform dopant distribution, then dopant profile uniformity improves, but manufacturing cost and process complexity increase
Solution Approach 1:
Multiple ion implantation steps with different tilt angles are merged into a single integrated doping process rather than requiring separate patterning and doping cycles. This consolidation achieves uniform dopant distribution while reducing the total number of process steps and associated costs.
3Productivity
If pitch size is reduced to increase device capacity, then device capacity increases, but maintaining uniform dopant profile becomes more difficult
Solution Approach 1:
By utilizing tilt angles as an additional processing dimension, the method maintains uniform dopant profiles even when lateral pitch dimensions are reduced. The multi-angle implantation approach ensures that dopants are distributed uniformly across the reduced pitch structures without requiring proportional reduction in doping precision.
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 uniform dopant profile in the selector layer enhances the reliability and efficiency of memory cells by minimizing cell-to-cell variation and reducing production costs, while maintaining process efficiency even at reduced pitch sizes.
Implementation Method 1
forming an initial selector layer by performing a first ion implantation of a dopant into the dielectric material layer at a first tilt angle and by performing a second ion implantation of the dopant into the dielectric material layer at a second tilt angle
Data Source
AI summary
A semiconductor device that includes: first conductive lines; second conductive lines disposed over the first lines to be spaced apart from the first lines; and a selector layer disposed between the first lines and the second lines and including a dielectric material and a dopant doped with a uniform dopant profile.