Metal Ring Precursors for Low-Temperature Phase Change Memory Deposition
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Solution Overview
Problem
Current methods for forming phase change material layers in phase-change random access memory (PRAM) devices face challenges in filling fine contact holes without void formation, particularly due to the high temperature requirements of conventional deposition methods which hinder device integration and increase grain size.
Innovation Solution
The use of metal ring compounds as precursors for low-temperature deposition, allowing for the formation of metal thin layers and phase change material layers at temperatures below 300°C, which enables stable filling of fine via holes with minimal void formation and smaller grain sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sputtering method is used to form phase change material layer, then deposition can be performed, but void formation occurs and step coverage is poor in fine via holes
Solution Approach 1:
The patent changes the deposition temperature parameter from conventional high temperature (700°C) to low temperature (below 300°C). This parameter change enables better step coverage and complete filling of fine via holes without void formation, while maintaining the phase change material's functional properties.
Solution Approach 2:
The patent uses composite metal precursors containing multiple metals (Ge, Sb, Te) in organic ligand structures. These composite precursors decompose at low temperatures to form the desired Ge-Sb-Te phase change material, enabling low temperature deposition with improved filling characteristics.
2Quantity of substance
If high temperature deposition (700°C) is used to form phase change material layer, then material can be deposited, but grain size increases and device integration becomes difficult
Solution Approach 1:
The patent fundamentally changes the deposition temperature parameter from 700°C to below 300°C by using organometallic precursors with labile ligands that decompose at low temperatures. This enables formation of phase change material layers with smaller grain sizes suitable for high-density device integration.
Solution Approach 2:
The patent introduces organic ligand intermediaries (such as beta-diketonates) that serve as carriers for metal atoms. These ligands facilitate low-temperature decomposition and material formation, acting as intermediaries between the metal sources and the final phase change material layer.
3Power
If contact surface area between bottom electrode and phase change material layer is reduced to increase current density, then effective current density increases, but filling fine via holes becomes more difficult
Solution Approach 1:
The patent changes the deposition temperature to below 300°C, which enables complete filling of fine via holes with smaller dimensions. This allows reduction of via hole size and contact area while maintaining reliable material filling, thereby increasing effective current density for reset programming.
Solution Approach 2:
The patent replaces the physical vapor deposition (sputtering) method with chemical vapor deposition using organometallic precursors. This substitution enables conformal coating and complete filling of high aspect ratio via holes through chemical decomposition and deposition mechanisms rather than physical bombardment.
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 enables the stable filling of fine contact holes with phase change material layers, reducing grain size and void formation, thereby improving device integration and performance in PRAM devices.
Implementation Method 1
supplying to a substrate at least one metal precursor having a metal ring compound... thereby forming a metal thin layer on the substrate
Implementation Method 2
when a writing current flows through the bottom electrode and the access device, joule heat is generated at an interface between the bottom electrode and the phase change material layer
Implementation Method 3
a phase change material layer in an amorphous state is heated to a temperature between a crystallization temperature (Tx) and a melting point (Tm) and then cooled. Thus, the phase change material layer is changed from the amorphous state to a crystalline state
Implementation Method 4
when the phase change material layer is heated to a temperature higher than the melting point (Tm) and the abruptly cooled, the phase change material layer is changed from a crystalline state to an amorphous state
Data Source
AI summary
The present invention provides metal precursors for low temperature deposition. The metal precursors include a metal ring compound including at least one metal as one of a plurality of elements forming a ring. Methods of forming a metal thin layer and manufacturing a phase change memory device including use of the metal precursors is also provided.