Nitride Semiconductor Gate Stack with Dual Silicon Nitride Films
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Solution Overview
Problem
Nitride-based semiconductor devices face current collapse and high gate leakage current issues, which affect their performance in power electronics and high-frequency applications, and existing solutions struggle to balance the suppression of these phenomena without compromising device stability.
Innovation Solution
A semiconductor device configuration using a high-oxygen-density first silicon nitride film as a gate insulation film and a low-oxygen-density second silicon nitride film as a surface passivation film, deposited using ECR plasma deposition and PE-CVD methods, respectively, to reduce interface state density and gate leakage current while maintaining channel mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a gate insulation film is used to reduce gate leakage current, then gate leakage current is reduced, but current collapse phenomenon occurs
Solution Approach 1:
The gate insulation structure is segmented into multiple layers: a first gate insulation film (silicon nitride) deposited by ECR plasma, and a second gate insulation film (silicon oxide or silicon oxynitride) deposited by PECVD. This segmentation allows each layer to perform different functions - the first layer suppresses current collapse while the second layer reduces gate leakage current, resolving the contradiction between these two opposing requirements.
Solution Approach 2:
The invention uses a composite gate insulation structure combining silicon nitride and silicon oxide/silicon oxynitride materials. The silicon nitride layer provides high dielectric strength to prevent current collapse, while the silicon oxide/silicon oxynitride layer provides low leakage properties. This composite approach allows simultaneous achievement of both current collapse suppression and gate leakage reduction.
2Strength
If a gate insulation film is used to increase breakdown voltage, then breakdown voltage is increased, but current collapse phenomenon occurs
Solution Approach 1:
The gate insulation structure is segmented into multiple layers: a first gate insulation film (silicon nitride) deposited by ECR plasma, and a second gate insulation film (silicon oxide or silicon oxynitride) deposited by PECVD. This segmentation allows each layer to perform different functions - the first layer suppresses current collapse while the second layer reduces gate leakage current, resolving the contradiction between these two opposing requirements.
Solution Approach 2:
The invention uses a composite gate insulation structure combining silicon nitride and silicon oxide/silicon oxynitride materials. The silicon nitride layer provides high dielectric strength to prevent current collapse, while the silicon oxide/silicon oxynitride layer provides low leakage properties. This composite approach allows simultaneous achievement of both current collapse suppression and gate leakage reduction.
3Reliability
If interface state density is reduced to suppress current collapse, then current collapse is suppressed, but gate leakage current increases
Solution Approach 1:
The gate insulation structure is segmented into multiple layers: a first gate insulation film (silicon nitride) deposited by ECR plasma, and a second gate insulation film (silicon oxide or silicon oxynitride) deposited by PECVD. This segmentation allows each layer to perform different functions - the first layer suppresses current collapse while the second layer reduces gate leakage current, resolving the contradiction between these two opposing requirements.
Solution Approach 2:
The invention uses a composite gate insulation structure combining silicon nitride and silicon oxide/silicon oxynitride materials. The silicon nitride layer provides high dielectric strength to prevent current collapse, while the silicon oxide/silicon oxynitride layer provides low leakage properties. This composite approach allows simultaneous achievement of both current collapse suppression and gate leakage reduction.
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 configuration effectively suppresses current collapse and reduces gate leakage current, achieving a balance that enhances the performance and stability of nitride-based semiconductor devices for power electronics and high-frequency operations.
Implementation Method 1
deposited using ECR plasma deposition and PE-CVD methods
Implementation Method 2
deposited using ECR plasma deposition and PE-CVD methods
Data Source
AI summary
A semiconductor device of an embodiment includes a semiconductor layer formed of a III-V group nitride semiconductor, a first silicon nitride film formed on the semiconductor layer, a gate electrode formed on the first silicon nitride film, a source electrode and a drain electrode formed on the semiconductor layer such that the gate electrode is interposed between the source electrode and the drain electrode, and a second silicon nitride film formed between the source electrode and the gate electrode and between the drain electrode and the gate electrode and having an oxygen atom density lower than that of the first silicon nitride film.