SiC Gate Dielectric Interface Passivation for Higher Channel Mobility
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Solution Overview
Problem
The growth of gate dielectric layers on silicon carbide (SiC) semiconductor devices leads to defects at the semiconductor-dielectric interface, resulting in low electron mobility and increased ON-resistance, necessitating larger active areas and higher costs.
Innovation Solution
A method involving surface cleaning and passivation of SiC substrates without exposure to oxidizing atmospheres, followed by dielectric layer formation, including a passivation layer to prevent native oxide formation and enhance channel mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate dielectric layers are grown on silicon carbide substrates using conventional methods, then the dielectric layer is formed, but defects propagate at the semiconductor-dielectric interface resulting in low electron mobility
Solution Approach 1:
The SiC substrate surface is cleaned and passivated before dielectric layer formation to prevent defect propagation. The cleaning step removes surface contaminants and the passivation step creates a protective interface, both performed prior to dielectric deposition to ensure a defect-free interface.
Solution Approach 2:
The substrate is treated in a nitrogen atmosphere during cleaning and passivation steps. The inert nitrogen environment prevents unwanted oxidation and contamination of the SiC surface, maintaining interface quality and preventing defect formation.
2Reliability
If nitridation anneal is performed to enhance interface mobility, then mobility improves, but mobility remains low compared to SiC bulk mobility requiring larger active area
Solution Approach 1:
The surface is cleaned and passivated before dielectric formation, creating an optimized interface structure that enables higher mobility without requiring post-growth nitridation. This preliminary interface preparation eliminates the need for additional annealing steps and achieves superior mobility results.
Solution Approach 2:
The interface structure is modified through controlled cleaning and passivation processes that change the chemical and physical parameters of the semiconductor-dielectric interface. This creates optimal conditions for carrier transport, achieving mobility接近 SiC bulk values.
3Reliability
If high channel resistance is compensated by increasing active area, then device performance is maintained, but manufacturing costs increase
Solution Approach 1:
The interface is prepared in advance through cleaning and passivation, creating optimal conditions for high mobility that eliminate the need for larger active areas. This preliminary optimization allows devices to achieve target performance with smaller, more cost-effective active areas.
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
Improves channel mobility and reduces ON-resistance, minimizing the need for larger active areas and lowering production costs.
Implementation Method 1
cleaning a surface area of the semiconductor substrate by removing oxide species, carbon clusters, or other contaminants
Implementation Method 2
surface passivation at the interface of the cleaned surface of the semiconductor substrate and the dielectric layer... protection of the surface of the semiconductor substrate by passivation means
Data Source
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AI summary
Herein, a method of forming a semiconductor device may comprise forming a semiconductor substrate comprising silicon carbide at a surface thereof, cleaning a surface area of the semiconductor substrate by removing oxide species, carbon clusters, or other contaminants, and forming a dielectric layer above the cleaned surface of the semiconductor substrate. The method further provides a surface passivation at the interface of the cleaned surface of the semiconductor substrate and the dielectric layer.