p+ Polysilicon Formation via Aluminum Diffusion
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Solution Overview
Problem
Current semiconductor devices face challenges such as short channel effects, sub-threshold slope non-scaling, and increased power dissipation as they approach sizes less than 100 nm, and existing non-volatile memory devices like Flash, Fe-RAM, MRAM, and PCRAM have limitations in scalability, compatibility, and reliability.
Innovation Solution
A method and device structure for a resistive switching device are developed, involving a semiconductor substrate with a dielectric material, aluminum wiring, and an intermix region formed through an annealing process to create a p+ polycrystalline silicon material and an amorphous silicon switching element, allowing for efficient non-volatile memory formation without costly implantation processes or equipment modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional doping processes are used to form p+ polysilicon material, then the desired impurity characteristic is achieved, but the manufacturing cost increases and process complexity increases
Solution Approach 1:
The patent extracts and eliminates the costly doping process step by utilizing the natural diffusion of aluminum species from the aluminum wiring material into the silicon material during the existing annealing process, achieving the p+ impurity characteristic without separate doping operations
Solution Approach 2:
The patent merges the formation of the aluminum-silicon alloy layer and the doping process into a single annealing step, where the aluminum wiring material simultaneously forms the alloy layer and provides the aluminum species that diffuse into silicon to create the p+ polysilicon material
2Stability of the object's composition
If high temperature annealing is used to crystallize silicon material, then polycrystalline silicon is formed, but aluminum spiking occurs in the polysilicon material
Solution Approach 1:
The patent performs preliminary formation of the aluminum-silicon alloy layer before the high temperature annealing process, creating a controlled interface structure that prevents uncontrolled aluminum diffusion (spiking) into the polysilicon material during subsequent thermal processing
Solution Approach 2:
The aluminum-silicon alloy layer acts as an intermediary layer between the aluminum wiring material and the polysilicon material, mediating the interaction during annealing and preventing direct, uncontrolled diffusion of aluminum into the polysilicon while still allowing sufficient aluminum species to reach the silicon for doping
3Productivity
If transistor size is reduced below 100 nm to continue scaling, then device density increases, but short channel effects and power dissipation increase
Solution Approach 1:
The patent changes the material parameters by forming a p+ polysilicon material with high aluminum content through controlled diffusion, creating a material with enhanced electrical properties that can maintain device performance at smaller dimensions by improving carrier concentration and reducing leakage currents
Solution Approach 2:
The patent creates a composite aluminum-silicon-polymer structure where the p+ polysilicon material combines silicon base with aluminum dopant species, forming a composite material that exhibits improved electrical characteristics suitable for scaled devices
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 eliminates the need for costly doping processes, reduces aluminum spiking, and enables the formation of a p+ polysilicon material at high temperatures, providing a scalable and reliable non-volatile memory solution with improved power efficiency and compatibility with existing processes.
Implementation Method 1
forming an intermix region by consuming a portion of the silicon material and a portion of the aluminum material using at least an anneal process
Implementation Method 2
the annealing process causes formation of a first alloy material from the intermix region
Implementation Method 3
the annealing process causes formation of a first alloy material from the intermix region and a polycrystalline silicon material
Data Source
AI summary
A method of forming a non-volatile memory device includes providing a substrate having a surface and forming a first dielectric overlying the surface, forming a first wiring comprising aluminum material over the first dielectric, forming a silicon material over the aluminum material to form an intermix region consuming a portion of the silicon material and aluminum material, annealing to formation a first alloy from the intermix region, forming a p+ impurity polycrystalline silicon over the first alloy material, forming a first wiring structure from at least a portion of the first wiring, forming a resistive switching element comprising an amorphous silicon material formed over the p+ polycrystalline silicon, and forming a second wiring structure comprising at least a metal material over the resistive switching element.