Semiconductor Capacitor Fabrication via Thermal Oxidation
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Solution Overview
Problem
Conventional semiconductor trench capacitors face limitations due to high resistance from polycrystalline silicon electrodes and high defect density in low-temperature chemically vapor-deposited dielectric layers, leading to reduced current capacity and reliability.
Innovation Solution
The method involves forming a dielectric lining layer using thermal oxidation in a pure oxygen environment, followed by the deposition of conductive capacitor plates with minimal interference, allowing for high-temperature processing that reduces defect density and enables the use of highly conductive materials, thereby enhancing capacitance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If chemical vapor deposition (CVD) is used to form the dielectric layer, then the dielectric can be formed at relatively low temperature (e.g., 600 degrees Celsius), but the resulting dielectric exhibits large defect density
Solution Approach 1:
The patent changes the processing temperature parameter from low temperature (600°C CVD) to high temperature (1200°C thermal oxidation), which fundamentally improves the dielectric quality by reducing defect density while forming the oxide layer
2Temperature
If low temperature CVD process is used for dielectric formation, then the process temperature is reduced (e.g., 600 degrees Celsius), but the dielectric layer exhibits high defect density and low reliability
Solution Approach 1:
The patent changes the temperature parameter from 600°C to 1200°C and changes the process method from CVD to thermal oxidation, which resolves the contradiction by achieving both acceptable temperature and high dielectric quality through the high-temperature oxidation process
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 results in capacitors with lower defect density, higher effective dielectric constant, and increased capacitance, addressing the limitations of conventional capacitors by improving current carrying capacity and reliability.
Implementation Method 1
forming a dielectric lining layer using thermal oxidation in a pure oxygen environment
Data Source
AI summary
A method of fabricating a semiconductor capacitor is disclosed. The method includes forming a first trench in a semiconductor substrate, forming a dielectric lining layer in the first trench, and depositing a first capacitor conductor plate layer on the dielectric lining layer. The method also includes forming a second trench such that the dielectric lining layer is exposed. The method also includes forming a third trench such that the dielectric lining layer is exposed within the third trench. The method also includes depositing a second capacitor conductor plate layer in the second trench and depositing a third capacitor conductor plate layer in the third trench. The method also includes forming a first electrical contact between the first capacitor conductor plate layer and the second capacitor conductor plate layer and forming a second electrical contact between the first capacitor conductor plate layer and the third capacitor conductor plate layer.