SiC Termination Insulating Films Preventing Charge Movement
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Solution Overview
Problem
The reliability of semiconductor devices is degraded due to variations in breakdown voltage and leakage current caused by charge movement in insulating films, particularly in wide bandgap semiconductor devices like SiC, where charge balance in the termination region is easily disrupted.
Innovation Solution
Incorporating a passivation film interposed between field oxide films to create an energy barrier that prevents horizontal charge movement, thereby maintaining charge balance and enhancing reliability by dividing the field oxide films and acting as an annular pattern surrounding the element region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If field oxide films are used in the termination region, then device reliability is improved through charge compensation, but charge movement in the insulating film causes variation in breakdown voltage and leakage current
Solution Approach 1:
The field oxide film is divided into multiple segments by introducing a second insulating film (passivation film) between first insulating films. This segmentation creates isolated charge compartments that prevent horizontal charge movement while maintaining vertical charge compensation functionality, thus resolving the contradiction between reliability improvement and charge balance stability.
Solution Approach 2:
A passivation film is introduced as an intermediary layer between the first insulating films in the termination region. This intermediate structure acts as a barrier to horizontal charge migration while allowing the field oxide films to maintain their charge compensation function, thereby stabilizing charge balance without compromising device reliability.
2Reliability
If a passivation film is interposed between field oxide films, then charge movement is prevented and reliability is improved, but device structure becomes more complex
Solution Approach 1:
The field oxide film structure is segmented by inserting passivation films at specific locations, creating a multi-layered configuration. While this increases structural complexity, it effectively prevents horizontal charge movement and stabilizes charge balance, achieving improved reliability that justifies the added complexity.
Solution Approach 2:
The passivation film is strategically positioned only in the termination region where charge compensation is needed, rather than throughout the entire device. This localized approach minimizes the increase in device complexity while maximizing the reliability improvement in the critical termination region.
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 solution effectively prevents charge movement in the termination region, improving the reliability of semiconductor devices by maintaining consistent breakdown voltage and reducing leakage current variations, especially in wide bandgap semiconductor devices like SiC.
Implementation Method 1
Incorporating a passivation film interposed between field oxide films to create an energy barrier that prevents horizontal charge movement
Data Source
AI summary
A semiconductor device according to an embodiment includes a semiconductor substrate having a first surface and a second surface. The semiconductor substrate includes an element region and a termination region provided around the element region. The termination region has a first semiconductor region of a first conductivity type provided at the first surface of the semiconductor substrate and a second semiconductor region of a second conductivity type provided between the first semiconductor region and the second surface. The semiconductor device further includes a first insulating film provided on the first semiconductor region, a second insulating film provided on the first semiconductor region and having a portion interposed between the first insulating films, a first electrode provided on the first surface of the element region and electrically connected to the first semiconductor region, and a second electrode provided at the second surface of the semiconductor substrate.