Nitrogen Doped GeSbTe CVD Composition Control
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Solution Overview
Problem
Phase Change Memory (PCM) technologies face challenges in controlling crystalline state resistance and SET speed due to difficulties in composition control of nitrogen doped GeSbTe materials during chemical vapor deposition, leading to high RESET currents and limited scaling for confined cell structures.
Innovation Solution
A method using a flow-modulated chemical vapor deposition apparatus to control the crystalline state resistance of nitrogen doped GeSbTe materials by adjusting the flow ratio of ammonia (NH3) to argon (Ar), allowing for the deposition of high crystalline resistance materials with fast crystallization speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional chemical vapor deposition is used to deposit nitrogen doped GeSbTe materials, then the phase change memory device can be fabricated, but the crystalline state resistance is low leading to high RESET currents
Solution Approach 1:
The patent applies parameter changes by modifying the deposition conditions including using a dual frequency RF plasma source with specific power ratios, controlling precursor flow rates, and adjusting chamber pressure to optimize nitrogen incorporation and achieve high crystalline state resistance while reducing RESET current
Solution Approach 2:
The patent creates a composite material structure by doping GeSbTe phase change material with nitrogen during chemical vapor deposition, forming a nitrogen-doped composite that exhibits enhanced crystalline state resistance and reduced RESET current compared to undoped materials
2Reliability
If the deposition process is optimized for high crystalline resistance, then RESET current is reduced, but the SET speed decreases
Solution Approach 1:
The patent applies dynamics by using a dual frequency RF plasma source that can dynamically adjust power distribution between frequencies, allowing real-time optimization of deposition conditions to achieve both high crystalline resistance and fast SET speed through controlled plasma chemistry
Solution Approach 2:
The patent optimizes multiple deposition parameters simultaneously including precursor flow rates, chamber pressure, and RF power ratios to achieve a balanced composition that provides both high crystalline state resistance for low RESET current and appropriate crystallization kinetics for fast SET speed
3Reliability
If the phase change material is doped with nitrogen to increase crystalline resistance, then RESET current is reduced, but the composition control becomes difficult
Solution Approach 1:
The patent implements feedback control by monitoring deposition parameters and adjusting precursor flow rates and RF power in response to measured film composition and properties, enabling precise control of nitrogen doping levels and GeSbTe stoichiometry to achieve target crystalline resistance
Solution Approach 2:
The patent replaces conventional single-frequency RF plasma control with a dual-frequency RF plasma system that provides independent control of ionization and excitation processes, enabling precise separation of nitrogen incorporation from GeSbTe deposition to improve composition control
4Device complexity
If conventional deposition methods are used, then the process is simple, but scaling for confined cell structures is limited
Solution Approach 1:
The patent replaces conventional thermal field deposition with a plasma-enhanced chemical vapor deposition system that uses electromagnetic fields to drive chemical reactions, enabling conformal deposition and precise composition control in confined cell structures while maintaining process feasibility
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 effectively reduces RESET current and improves SET speed by tuning the NH3/Ar flow ratio, enabling the fabrication of high-density phase change memory devices with reduced power consumption and increased memory array speed.
Implementation Method 1
flowing gas precursors into the flow modulated chemical vapor deposition apparatus to provide the base material components of the phase change material
Implementation Method 2
flowing a co-reactant precursor of ammonia (NH3) and an inert gas of argon (Ar) into the flow modulated chemical vapor deposition, wherein adjusting ratio of the co-reactant precursor to the inert gas adjusts the crystalline state resistance of the phase change material
Data Source
AI summary
A method of forming a phase change material is provided in which the crystalline state resistance of the material can be controlled through controlling the flow ratio of NH3/Ar. The method may include providing a flow modulated chemical vapor deposition apparatus. The method may further include flowing gas precursors into the flow modulated chemical vapor deposition apparatus to provide the base material components of the phase change material. The method further includes flowing a co-reactant precursor and an inert gas into the flow modulated chemical vapor deposition, wherein adjusting ratio of the co-reactant precursor to the inert gas adjusts the crystalline state resistance of the phase change material.