Undoped HfO2 Ferroelectric Memory via Thermal Annealing
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Solution Overview
Problem
Current semiconductor devices face challenges in integrating ferroelectric materials compatible with advanced technology nodes, particularly due to complex doping processes and poor compatibility with standard CMOS processes, leading to issues with throughput and uniformity in ferroelectric non-volatile memory devices.
Innovation Solution
A semiconductor device and method involving an undoped amorphous HfO2 layer with a TiN layer, where thermal annealing induces a ferroelectric phase in the HfO2 layer, enabling ferroelectric behavior without the need for doping, thus simplifying the process flow and improving compatibility with standard CMOS processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doped hafnium oxide materials are used to achieve ferroelectric behavior, then ferroelectric properties are obtained, but process complexity and doping uniformity deteriorate
Solution Approach 1:
The patent removes the dopant element from the hafnium oxide material system, using pure undoped HfO2 instead of doped variants. This extraction of the dopant simplifies the material composition and eliminates the complex doping processes while maintaining ferroelectric behavior through alternative mechanisms such as oxygen vacancies or specific crystalline phase engineering.
Solution Approach 2:
The patent changes key material parameters including oxygen stoichiometry, crystalline phase structure, and processing conditions to induce ferroelectricity in undoped HfO2. By controlling parameters like oxygen partial pressure during deposition, annealing temperature, and layer thickness, the material achieves ferroelectric properties without requiring dopant elements.
2Reliability
If doped hafnium oxide materials are used to achieve ferroelectric behavior, then ferroelectric properties are obtained, but compatibility with standard CMOS processes deteriorates
Solution Approach 1:
By removing the dopant component from the material system, the patent eliminates processing steps that are incompatible with standard CMOS fabrication. Undoped HfO2 can be deposited and processed using conventional CMOS-compatible techniques such as atomic layer deposition (ALD) and standard annealing processes, avoiding the need for specialized doping equipment and procedures.
3Reliability
If doped hafnium oxide materials are used to achieve ferroelectric behavior, then ferroelectric properties are obtained, but manufacturing throughput and uniformity deteriorate
Solution Approach 1:
The elimination of dopant materials and doping processes reduces the number of fabrication steps required, thereby increasing manufacturing throughput. Undoped HfO2 layers can be deposited in a single continuous process without intermediate doping steps, and the uniformity of the material is improved by eliminating dopant distribution variations that typically plague doped semiconductor materials.
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 allows for the easy implementation of ferroelectricity in semiconductor devices, enhancing memory performance and scalability while maintaining compatibility with existing manufacturing techniques, thereby improving the reliability and uniformity of ferroelectric non-volatile memory devices.
Implementation Method 1
performing a thermal annealing process for at least partially inducing a ferroelectric phase in the undoped amorphous HfO2 layer
Implementation Method 2
thermal annealing induces a ferroelectric phase in the HfO2 layer, enabling ferroelectric behavior
Data Source
AI summary
The present disclosure provides a semiconductor device comprising a substrate, an undoped HfO2 layer formed over the substrate and a TiN layer formed on the HfO2 layer. Herein, the undoped HfO2 layer is at least partially ferroelectric. In illustrative methods for forming a semiconductor device, an undoped amorphous HfO2 layer is formed over a semiconductor substrate and a TiN layer is formed on the undoped amorphous HfO2 layer. A thermal annealing process is performed for at least partially inducing a ferroelectric phase in the undoped amorphous HfO2 layer.