Nitride HEMT Multi-Field-Plate Structure for Breakdown-Frequency Tradeoff
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Solution Overview
Problem
The configuration of field plates in nitride-based semiconductor devices induces parasitic capacitances, limiting the maximum operating frequency and degrading the electrical properties and reliability of high-electron-mobility transistors (HEMTs) used in high power and high frequency applications.
Innovation Solution
A semiconductor device design featuring multiple overlapping field plates, where the second field plate is horizontally spaced away from the gate electrode, reducing parasitic capacitance and improving electric field distribution, is implemented. This configuration includes a first nitride-based semiconductor layer, a second nitride-based semiconductor layer with a greater bandgap, and electrodes with field plates extending to cover specific regions to modulate the electric field effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If field plates are adopted to modulate electrical field distribution, then breakdown phenomenon is avoided, but parasitic capacitances are induced which limit maximum operating frequency
Solution Approach 1:
The patent divides the field plate structure into multiple segments (first field plate and second field plate) positioned at different locations. This segmentation allows each field plate segment to independently modulate the electrical field in its respective region, achieving comprehensive breakdown protection while minimizing total parasitic capacitance compared to a single large field plate.
Solution Approach 2:
The patent applies field plates selectively at specific locations where breakdown is most likely to occur, rather than using a continuous field plate across the entire device. The first field plate is positioned at a first location and the second field plate at a second location, creating localized field modulation exactly where needed, thus reducing overall parasitic capacitance while maintaining reliability.
2Reliability
If field plates are configured to cover specific regions, then electrical field distribution is improved, but device complexity increases
Solution Approach 1:
The field plate is segmented into multiple discrete components (first field plate and second field plate) that can be independently designed and positioned. This segmentation simplifies the overall configuration by allowing each segment to be optimized for its specific location, making the complex task of field distribution management more manageable through modular design.
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
The multi-field-plate configuration alleviates the negative impact of parasitic capacitance, enhancing the electrical properties and reliability of the semiconductor device by achieving a better electric field distribution and reducing stress accumulation, thereby improving the device's performance in high power and high frequency applications.
Implementation Method 1
III-nitride-based HEMTs utilize a heterojunction interface between two materials with different bandgaps to form a quantum well-like structure, which accommodates a two-dimensional electron gas (2DEG) region
Implementation Method 2
heterojunction interface between two materials with different bandgaps to form a quantum well-like structure, which accommodates a two-dimensional electron gas (2DEG) region
Implementation Method 3
field plates are adopted to modulate electrical field distribution therein
Data Source
AI summary
A semiconductor device includes a first and a second nitride-based semiconductor layers, a first and a second electrodes, a first gate electrode, a first and a second field plates. The first field plate is disposed over the second nitride-based semiconductor layer and extends from a region between the first electrode and the first gate electrode to a region directly over the first gate electrode. The second field plate is disposed over the second nitride-based semiconductor layer and extends from a region between the first electrode and the first field plate to a region directly over the first field plate. The second field plate is horizontally spaced away from the first gate electrode.