SiC Trench Structure With Oxide Interface Stabilization
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Solution Overview
Problem
Trench silicon carbide devices experience high-density interface states at the interface between silicon dioxide and silicon carbide substrates, leading to delamination and malfunction due to carbon-related bonding issues, which reduces their reliability.
Innovation Solution
A semiconductor device structure is developed with trench and mesa structures, where a silicon dioxide first oxide layer is formed on the trench sidewalls, followed by a conductive layer, a second oxide layer, a dielectric layer, and an insulation layer, with thermal oxidation treatment to reduce interface states and enhance reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If trench structures are formed on silicon carbide substrate, then device power handling capability is improved, but interface state density increases causing delamination and malfunction
Solution Approach 1:
A nitrogen-containing oxide layer is introduced as an intermediary between the silicon dioxide layer and the silicon carbide substrate. This intermediate layer acts as a mediator that reduces the high-density interface states at the SiO2-SiC interface, preventing delamination and device malfunction while maintaining the trench structure's power handling capability
Solution Approach 2:
The chemical composition of the oxide layer is modified by incorporating nitrogen elements. This parameter change in the oxide layer's composition transforms it from a standard silicon dioxide layer to a nitrogen-containing oxide layer, which effectively reduces interface state density and improves device reliability
2Reliability
If thermal oxidation treatment is performed, then interface states are reduced and reliability is improved, but manufacturing process complexity increases
Solution Approach 1:
The nitrogen-containing oxide layer is formed in advance before subsequent device fabrication steps. This preliminary action prepares the interface with reduced state density beforehand, ensuring reliable device operation throughout the manufacturing process without requiring additional complex interventions later
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 effectively reduces interface states and delamination risks, improving the reliability and performance of trench silicon carbide devices by increasing viscosity between oxide layers and silicon carbide substrates, thus enhancing their operational stability.
Implementation Method 1
Via a thermal oxidation treatment, oxygen flows through the first oxide layer and reaches to the silicon carbide substrate that is connected to the first oxide layer, and the silicon carbide substrate is oxidized and forms a thermal oxide layer
Implementation Method 2
performing thermal oxidation treatment... the silicon carbide substrate is oxidized and forms a thermal oxide layer... increasing viscosity between oxide layers and silicon carbide substrates
Data Source
AI summary
A semiconductor device is disclosed herein. The semiconductor device includes a silicon carbide substrate, trench structures, mesa structures, a first oxide layer, a conductive layer, a second oxide layer, a dielectric layer, and an insulation layer. The trench structures are formed on a surface of the silicon carbide substrate. Each trench structure has sidewalls and a bottom, and each respective mesa structure is formed between the respective adjacent trench structures. The first oxide layer is formed on the sidewalls of the trench structures. The conductive layer is formed on the bottom of the trench structures and on a top surface of each mesa structure. The second oxide layer is formed on the first oxide layer and the conductive layer. The dielectric layer is formed on the second oxide layer. The insulation layer is formed on the dielectric layer.