GST Phase-Change Layer Deposition for Stable 3D Memory Cells
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Solution Overview
Problem
There is a need for improved phase change materials with enhanced durability, phase stability, conformal deposition, and homogeneous composition, as well as phase change memory cells with high endurance.
Innovation Solution
A method involving cyclical deposition processes, such as atomic layer deposition, is used to form layers comprising a group 14 element, a pnictogen, and a chalcogen, utilizing multiple precursor pulses and sub-cycles with different precursors to achieve precise compositional control and conformal deposition on substrates with three-dimensional features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional phase change materials are used, then the deposition process is simple, but the durability and phase stability are insufficient
Solution Approach 1:
The deposition process is segmented into multiple sequential pulses within each deposition cycle, where different precursors (group 14 element, pnictogen, chalcogen) are deposited in a specific sequence. This segmentation allows precise control over the compositional ratios and spatial distribution of elements, thereby improving durability and phase stability while managing process complexity through systematic structuring
Solution Approach 2:
The invention changes multiple parameters simultaneously including precursor selection, deposition temperature, pulse duration, and compositional ratios. By optimizing these parameters in the cyclical deposition process, the method achieves improved phase stability and durability. The use of multiple precursors with controlled deposition parameters enables precise tuning of material properties
2Ease of operation
If conventional deposition methods are used, then the process is fast, but conformal deposition on complex substrates is not achieved
Solution Approach 1:
The invention employs periodic cyclical deposition where each cycle consists of sequential precursor pulses followed by purge steps. This periodic action allows reactants to diffuse uniformly across complex substrate surfaces during each pulse, achieving conformal coverage. The cyclic nature with controlled pulse durations ensures complete surface coverage while maintaining reasonable deposition rates through repeated cycles
Solution Approach 2:
The method performs preliminary surface preparation and controlled precursor adsorption during each deposition cycle before final material formation. The sequential pulse structure allows precursor molecules to pre-adsorb uniformly on the substrate surface, ensuring conformal deposition on complex geometries before the actual material layer is completed
3Stability of the object's composition
If single precursor deposition is used, then the process is simple, but homogeneous phase change materials are not formed
Solution Approach 1:
The deposition process is segmented into distinct pulses for each precursor type (group 14 element, pnictogen, chalcogen) within a unified deposition cycle. This segmentation ensures that each precursor is deposited in a controlled manner with precise timing, allowing uniform distribution and homogeneous mixing of elements in the final phase change material layer
Solution Approach 2:
The invention merges multiple precursor deposition processes into a single integrated cyclical deposition system. By combining the deposition of different precursors in a coordinated sequence within each cycle, the method achieves homogeneous phase change materials with controlled compositional ratios, managing complexity through unified process integration
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 method enables the formation of phase change materials with improved durability, stability, and compositional control, allowing for high-endurance phase change memory cells.
Implementation Method 1
executing a plurality of deposition cycles, a deposition cycle comprising a group 14 element pulse, a pnictogen pulse, and a chalcogen pulse
Data Source
AI summary
Disclosed are methods for forming layers comprising a group 14 element, a pnictogen, and a chalcogen. In some embodiments, the group 14 element comprises germanium, the pnictogen comprises antimony, and the chalcogen comprises tellurium. The methods comprise executing a plurality of deposition cycles. A deposition cycle comprises exposing a substrate to two different group 14 precursors, to two different pnictogen precursors, or to two different chalcogen precursors. Further discloses are related systems and methods. Suitable systems include atomic layer deposition systems. Suitable devices include phase change memory devices.