Doped HZO Layer Gradient for Low-Leakage Ultra-Thin Capacitors
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Solution Overview
Problem
The semiconductor industry faces challenges with Hafnium Zirconium Oxide (HfZrO) films in ultra-thin capacitors due to high leakage currents and non-linear Capacitance Voltage (CV) characteristics, which are exacerbated as film thickness decreases below 45 angstroms, making integration into devices challenging.
Innovation Solution
A method involving a cyclic process to form a doped hafnium zirconium oxide (HZO) layer on a substrate by pulsing hafnium, zirconium, oxygen, and dopant precursors in a reaction chamber, creating a dopant concentration gradient, and forming a layered structure with varying dopant concentrations to enhance dielectric constant and reduce leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If HfZrO film thickness is reduced below 45 angstroms to achieve smaller capacitor size, then capacitor miniaturization is improved, but leakage current increases and exceeds acceptable limits
Solution Approach 1:
The patent applies local quality by creating a dopant concentration gradient within the HfZrO layer, where the dopant concentration varies from the first interface to the second interface. This gradient structure provides different local properties: regions with higher dopant concentration suppress leakage current, while maintaining the overall thin film structure for miniaturization. The dopant concentration ranges from 0.0 to 20.0% across the layer thickness, optimizing both size and reliability.
Solution Approach 2:
The patent changes the parameter of dopant concentration within the HfZrO layer to resolve the contradiction. By introducing dopants at varying concentrations (0.0 to 20.0%) and creating a concentration gradient through cyclic pulsing, the material properties are modified to reduce leakage current while maintaining the thin film thickness required for capacitor miniaturization.
2Length of moving object
If HfZrO film thickness is reduced to 15-20 angstroms for advanced technology nodes, then device scaling is improved, but leakage current exacerbates and becomes unmanageable
Solution Approach 1:
At the extreme thinness of 15-20 angstroms, the patent applies local quality by implementing a dopant concentration gradient where dopant concentration varies from 0.0 to 20.0% across the film thickness. This creates localized regions with different electrical properties, suppressing leakage current at critical interfaces while maintaining the ultra-thin overall structure for advanced device scaling.
Solution Approach 2:
The patent creates a composite structure by doping HfZrO with additional elements at varying concentrations. This composite material approach modifies the electrical properties of the ultra-thin film, enabling it to function reliably at 15-20 angstroms thickness by reducing leakage current through the dopant-induced changes in material properties.
3Quantity of substance
If HfZrO is used to achieve high dielectric constant value k above 40, then capacitance density is improved, but CV non-linearity and asymmetry increase making integration challenging
Solution Approach 1:
The patent changes the parameter of dopant concentration (0.0 to 20.0%) and creates a concentration gradient to modify the CV characteristics of HfZrO. This parameter modification linearizes the CV response and reduces asymmetry, making the high-capacitance-density material suitable for practical device integration while maintaining the dielectric constant value k above 40.
Solution Approach 2:
By creating a dopant concentration gradient rather than uniform doping, the patent achieves local optimization of electrical properties. Different regions of the HfZrO layer have different dopant concentrations, which collectively linearize the overall CV characteristic and reduce asymmetry, enabling integration while preserving high capacitance density.
4Reliability
If Post Deposition Anneal (PDA) is used to reduce leakage in ultra-thin films, then leakage reduction is achieved, but process window becomes narrow and integration becomes difficult
Solution Approach 1:
The patent applies preliminary action by incorporating dopants during the deposition process itself, creating a dopant concentration gradient before the film is complete. This pre-doping approach reduces leakage current intrinsically, eliminating or reducing the need for subsequent PDA processing, thereby widening the process window and improving ease of manufacture and integration.
Solution Approach 2:
The patent extracts the leakage reduction function from a separate post-deposition annealing step and integrates it into the deposition process itself through dopant incorporation. This eliminates the need for narrow-window PDA processes, simplifying the manufacturing flow and improving integration ease while maintaining reliability.
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 achieves a high dielectric constant value with linear CV characteristics and reduced leakage, suitable for next-generation Metal-Insulator-Metal capacitors (MIM CAPS) in logic and memory applications.
Implementation Method 1
A method involves a cyclic process to form a doped hafnium zirconium oxide (HZO) layer on a substrate by pulsing hafnium, zirconium, oxygen, and dopant precursors in a reaction chamber
Data Source
AI summary
Disclosed herein is a method, system and apparatus for forming, by a cyclic process, a dopant concentration gradient in a doped hafnium zirconium oxide (HZO) layer on a substrate, the cyclic process includes, providing the substrate in a reaction chamber, a) pulsing a hafnium precursor(s) into the reaction chamber, where at least a part of the substrate is contacted with the hafnium precursor(s), b) pulsing a zirconium precursor(s) into the reaction chamber, where at least a part of the substrate is contacted with the zirconium precursor(s), c) pulsing an oxygen reactant(s) into the reaction chamber, where at least a part of the substrate is contacted with the oxygen reactant(s), d) pulsing a dopant precursor(s) into the reaction chamber, where at least a part of the substrate is contacted with the dopant precursor(s), and e) purging the reaction chamber.