Embedded Sensor Wells in Wide Bandgap Semiconductors
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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 close to the semiconductor die, then area is reduced, but measurement accuracy deteriorates due to parasitic signals
Solution Approach 1:
A shielding well structure is introduced as an intermediary element between the sensor element and the drift layer. This shielding well, doped with opposite polarity to the drift layer, acts as a mediator that blocks parasitic signals from reaching the sensor element, thereby maintaining measurement accuracy while allowing the sensor to be placed close to the power device structure.
Solution Approach 2:
The solution moves from a two-dimensional planar arrangement to a three-dimensional vertical structure by introducing the shielding well that extends downward from the sensor element into the drift layer. This vertical dimension provides electromagnetic shielding without increasing the horizontal footprint, enabling compact integration while maintaining sensor accuracy.
2Area of stationary object
If embedded sensor elements are integrated into wide bandgap power semiconductor devices, then area is reduced and accuracy is improved, but device complexity increases due to additional shielding structures
Solution Approach 1:
The shielding well structure serves multiple functions simultaneously: it provides electromagnetic shielding for the sensor element, acts as a doping region that can be integrated with existing device fabrication processes, and creates isolation regions that prevent parasitic signal paths. This multi-functionality reduces the need for separate dedicated shielding components, thereby managing complexity while achieving integration.
Solution Approach 2:
The sensor element and shielding structures are merged into a single integrated unit within the semiconductor device. The shielding well is doped in conjunction with the sensor element formation process, combining what could be separate components into one unified structure, thereby reducing overall device complexity despite the added functionality.
3Measurement precision
If shielding wells and noise reduction wells are added to isolate the sensor element, then parasitic signal interference is reduced, but manufacturing complexity increases
Solution Approach 1:
The shielding wells are doped and formed during the preliminary stages of device fabrication, before the sensor element is fully assembled and operational. By establishing the shielding structure in advance during the doping process, the patent avoids the need for complex post-assembly shielding operations, thereby simplifying manufacturing despite the additional structural elements.
Solution Approach 2:
The shielding well utilizes doping concentration and type as controllable parameters to achieve shielding functionality. By adjusting the doping parameters (concentration, type, depth) during standard semiconductor fabrication processes, the patent implements complex shielding behavior through simple parameter adjustments rather than complex structural additions, easing manufacturing.
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.