DRAM Capacitor Electrode Oxide Structure for High Capacitance, Low Stress
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Solution Overview
Problem
As semiconductor devices become more integrated and require higher capacitance, existing capacitor structures face challenges in achieving improved capacitance while minimizing stress, particularly in dynamic random access memory (DRAM) devices.
Innovation Solution
A capacitor structure is designed with a lower electrode, a capacitor dielectric film, and an upper electrode, where the electrodes include doped oxide films and metal oxide films, specifically using zirconium and hafnium oxides to enhance dielectric constant and reduce stress, and a method for manufacturing this structure involving sequential deposition and heat treatment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a capacitor structure is designed with high-capacity requirements in DRAM devices, then capacitance is improved, but stress increases due to material constraints and design rule shrinkage
Solution Approach 1:
The patent employs composite electrode structures combining multiple metal materials (e.g., tungsten, copper, aluminum) with oxide layers (e.g., tungsten oxide, copper oxide) to achieve both high capacitance and stress reduction. The composite nature allows optimization of electrical properties while managing mechanical stress through material selection and layer configuration.
Solution Approach 2:
The patent modifies material parameters by controlling oxidation states, doping concentrations, and layer thicknesses of the electrode and dielectric materials. By adjusting these parameters, the capacitance is enhanced while stress is managed through controlled material properties and interface characteristics.
2Productivity
If design rules are decreased to increase integration, then device density is improved, but capacitance maintenance becomes more difficult
Solution Approach 1:
The patent applies different material compositions and structures to specific regions of the capacitor electrode (e.g., gradient doping, varying oxide thickness) to optimize local electrical properties. This allows maintaining high capacitance in scaled-down structures by tailoring material properties at different locations within the capacitor stack.
Solution Approach 2:
The patent transitions from planar capacitor structures to vertically stacked configurations with multiple electrode and dielectric layers. This dimensional change allows increased capacitance density by utilizing the vertical dimension, compensating for the reduced lateral dimensions imposed by scaled design rules.
3Quantity of substance
If metal materials are doped into electrodes to increase capacitance, then capacitance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent incorporates doping elements and oxide layers during the initial electrode formation processes rather than adding them separately later. By performing doping and oxidation steps as integrated parts of the electrode fabrication sequence, the patent achieves enhanced capacitance while minimizing additional manufacturing steps and complexity.
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 proposed structure achieves improved capacitance and reduced stress in semiconductor memory devices, effectively addressing the capacitance requirements of advanced DRAM devices while maintaining structural integrity.
Implementation Method 1
a first doped oxide film disposed between the lower electrode film and the capacitor dielectric film, wherein the first doped oxide film includes a second metal element and an oxide of the first metal element
Data Source
AI summary
A capacitor structure includes lower and electrodes, and a capacitor dielectric film interposed therebetween. The lower electrode includes a lower electrode film including a first metal element, a first doped oxide film including a second metal element and an oxide of the first metal element, and a first metal oxide film. The first metal oxide film includes an oxide of the first metal element and is free of the second metal element. The upper electrode includes an upper electrode film including the first metal element, a second doped oxide film including the second metal element and an oxide of the first metal element, and a second metal oxide film that includes an oxide of the first metal element, and is free of the second metal element.