Crystalline HfSiO2 Dielectric for EOT Scalability
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Solution Overview
Problem
The challenge in scaling down integrated circuit capacitors lies in reducing the effective oxide thickness (EOT) while maintaining functional features, particularly due to difficulties in manufacturing exceedingly thin dielectric regions, which is exacerbated by the limitations of current dielectric materials like silicon oxy-nitride reaching its scalability limits and causing Fermi-Level Pinning issues with high-k gate dielectrics.
Innovation Solution
The integration of crystalline phase hafnium silicon oxide (HfSiO2) with a dielectric constant of approximately 40 is achieved through a selective formation process and thermal treatment, allowing for EOT scalability by using area masking and atomic layer deposition (ALD) to form amorphous HfSiO2, which is then converted to crystalline HfSiO2, reducing thermal budget and addressing etching difficulties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dielectric materials like silicon oxy-nitride are used, then manufacturing process is simpler, but EOT scalability is limited and Fermi-Level Pinning issues occur
Solution Approach 1:
The patent changes the dielectric constant parameter by transitioning from conventional materials (k≈7-8) to high-k crystalline HfSiO2 (k≈40), enabling EOT scalability while maintaining manufacturing feasibility through selective area formation and thermal treatment processes
Solution Approach 2:
The patent employs composite material strategy by forming HfSiO2 in specific crystalline phases (tetragonal or cubic) within a dielectric stack, combining high dielectric constant with manageable manufacturing properties through controlled crystallization
2Temperature
If amorphous HfSiO2 is formed first, then thermal budget is reduced, but additional thermal treatment step is required
Solution Approach 1:
The patent performs preliminary formation of amorphous HfSiO2 using ALD at lower temperatures, then applies a subsequent thermal treatment to crystallize the material in-situ, avoiding the need for high-temperature processing during initial deposition
Solution Approach 2:
The crystalline HfSiO2 phase is formed in-situ within the capacitor structure through thermal treatment of the amorphous precursor, eliminating the need for separate crystallization processing steps and reducing overall process complexity
3Volume of moving object
If capacitor size is reduced, then circuit scaling is achieved, but EOT reduction becomes increasingly difficult
Solution Approach 1:
The patent changes the dielectric constant parameter by transitioning from conventional materials (k≈7-8) to high-k crystalline HfSiO2 (k≈40), enabling EOT scalability while maintaining manufacturing feasibility through selective area formation and thermal treatment processes
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 effective oxide thickness scalability for several generations of reduced scale architecture by overcoming etching challenges and reducing Fermi-Level Pinning, thus improving the performance of scaled capacitors.
Implementation Method 1
using area masking and atomic layer deposition (ALD) to form amorphous HfSiO2
Implementation Method 2
which is then converted to crystalline HfSiO2
Data Source
AI summary
In an embodiment of the invention, an amorphous phase dielectric material is selectively formed over a substrate. The amorphous phase dielectric material is then converted into a crystalline phase dielectric material.