GaN Power Element Well Layout for Substrate Stress Equalization
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Solution Overview
Problem
In current monolithically integrated GaN-based electrical devices, the substrate experiences electrical stress different from the upper and lower power elements, affecting their performance and stability.
Innovation Solution
A microelectronic device with spaced-apart doped well regions in the substrate, each having an opposite doping type to the substrate, and power elements connected to these well regions, with low potential terminals electrically connected to the well regions, forming a cascade configuration to equalize potential and enhance electrical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If monolithic integration of GaN-based power elements is implemented, then device weight reduction and integration density improvement are achieved, but electrical stress mismatch between substrate and power elements causes performance degradation
Solution Approach 1:
The substrate is segmented into multiple doped well regions with different doping types and concentrations, allowing different areas to provide different electrical characteristics. This segmentation enables each power element to be associated with a specifically designed well region that matches its electrical stress requirements, resolving the contradiction between integration density and performance stability.
Solution Approach 2:
Different regions of the substrate are doped with different types and concentrations of dopants to create local variations in electrical properties. Each doped well region is tailored to match the specific electrical stress conditions of the power element it supports, thereby maintaining high integration density while ensuring each element operates under optimal electrical conditions.
2Reliability
If doped well regions are introduced to equalize electrical stress, then performance stability is improved, but device structure and manufacturing process become more complex
Solution Approach 1:
The doped well regions are merged with the substrate formation process itself, using the same epitaxial growth technique to create both the substrate structure and the doped well regions. This integration of functions reduces overall device complexity despite the added functionality of stress equalization.
Solution Approach 2:
The doped well regions serve multiple functions: they provide electrical stress equalization, act as isolation structures between power elements, and enable potential future expansion of device functionality. This multi-functionality justifies the increased structural complexity by delivering multiple benefits from a single structural feature.
3Reliability
If doped well regions are introduced to equalize electrical stress, then manufacturing process becomes more complex, but performance stability is improved
Solution Approach 1:
The doped well regions are formed during the epitaxial growth process before the power elements are fabricated. This preliminary action incorporates the stress equalization structure into the substrate itself, avoiding the need for additional post-processing steps and simplifying the overall manufacturing flow despite the increased process complexity.
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 stabilizes the performance of power elements by preventing electron trapping in defects, improving the reliability and stability of the GaN integrated circuit.
Implementation Method 1
at least two doped well regions in the substrate, each having a doping type opposite to that of the substrate
Data Source
AI summary
A microelectronic device includes a substrate, at least two doped well regions, an epitaxial structure, and at least two power elements. The doped well regions are disposed in the substrate, and are spaced apart from each other. Each of the doped well regions has a doping type opposite to that of the substrate. The epitaxial structure is disposed on the substrate, and is in contact with the doped well regions. The power elements are disposed on the epitaxial structure opposite to the substrate, and are cascade connected with each other. A low potential terminal of each of the power elements is electrically connected to a respective one of the doped well regions. A method for making the microelectronic device is also provided.