Wide-Bandgap Sensor Shielding for Accurate Embedded Temperature Sensing
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Solution Overview
Problem
Wide bandgap semiconductor devices face challenges in integrating embedded sensor elements due to high sheet resistance and parasitic signals, leading to reduced accuracy and increased area, especially when monitoring parameters like temperature for control adjustments.
Innovation Solution
Incorporating an embedded sensor element, such as a temperature sensing diode, within the semiconductor device with a shielding well and noise reduction well, and minimizing the distance between contact wells to reduce parasitic interference, while using an insulating layer and additional functional layers for further isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If discrete sensor elements are placed in close proximity to the semiconductor die, then the device area is reduced, but measurement accuracy deteriorates due to parasitic signals
Solution Approach 1:
The device is segmented into distinct functional regions: the power semiconductor die and the sensor element are separated onto different substrates. This spatial segmentation allows the sensor to be positioned close to the die for compactness while maintaining measurement accuracy by reducing parasitic signal interference through substrate isolation.
Solution Approach 2:
A separate substrate acts as an intermediary between the power semiconductor die and the sensor element. This intermediary substrate provides mechanical support and electrical isolation, enabling the sensor to be placed in close proximity to the die while maintaining measurement accuracy by blocking parasitic signal paths.
2Measurement precision
If embedded sensor elements are integrated onto the die, then measurement accuracy improves, but device complexity increases due to manufacturing challenges
Solution Approach 1:
The device architecture is segmented into two independent parts: the power semiconductor die and the sensor element on a separate substrate. This segmentation avoids the manufacturing complexity of integrating sensors directly into wide bandgap devices while maintaining the benefits of close proximity mounting and high measurement accuracy.
Solution Approach 2:
The sensor element is extracted from the power semiconductor die structure and placed on a separate substrate. This extraction eliminates the manufacturing challenges associated with integrating sensors into wide bandgap devices while preserving measurement accuracy through close coupling via the substrate.
3Object-affected harmful factors
If the distance between contact wells is minimized, then parasitic signal isolation improves, but manufacturing precision requirements increase
Solution Approach 1:
Contact wells are positioned at strategic locations to create equipotential regions that minimize voltage gradients across the substrate. By minimizing the distance between contact wells, the substrate potential becomes more uniform, reducing parasitic signal paths while the symmetrical arrangement helps mitigate manufacturing precision requirements.
Solution Approach 2:
The substrate structure incorporates localized features with different properties: regions with minimized contact well distances for parasitic signal isolation, and other regions optimized for manufacturing tolerances. This local quality differentiation allows parasitic signal isolation to be enhanced in critical areas without uniformly increasing manufacturing precision requirements across the entire device.
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 enables accurate and compact measurement of operating parameters, providing effective isolation from parasitic signals and reducing interference, thus enhancing the functionality and reliability of wide bandgap power semiconductor devices.
Implementation Method 1
a shielding well having a doping type opposite the doping type of the drift layer may be provided below the embedded sensor element in the drift layer. The shielding well may provide additional isolation for the embedded sensor element from parasitic signals.
Implementation Method 2
The noise reduction well may reduce the resistance at the surface of the drift layer below the embedded sensor element, thereby providing additional isolation of the embedded sensor element from parasitic signals.
Data Source
AI summary
Shielding techniques are used to provide an embedded sensor element such as a temperature sensing element on a wide bandgap power semiconductor device. A semiconductor device may include a drift layer and an embedded sensor element. The drift layer may be a wide bandgap semiconductor material. A shielding structure is provided in the drift layer below the embedded sensor element. The embedded sensor element may be provided between contacts that are in electrical contact with the shielding well. The distance between the contacts may be minimized. A noise reduction well may be provided between the contacts to further isolate the embedded sensor element from parasitic signals.