GaN Semiconductor Back Surface Isolation via Segmented Wells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional GaN semiconductor devices face challenges in independently controlling substrate potentials, leading to issues like inadvertent device turn-on, resistance increase, and heat management, especially in high-frequency and high-voltage applications, where the substrate potential can interfere with device operation and heat dissipation.
Innovation Solution
The implementation of implanted wells or diffused conductive regions, combined with via connections, allows for the electrical isolation of substrate regions from each other, enabling independent control of substrate potentials and heat sink configurations, thereby isolating the back surface potential from the substrate potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the substrate is used as a common electrical reference for multiple GaN devices, then device integration is simplified, but substrate potential interference causes inadvertent device turn-on and resistance increase
Solution Approach 1:
The substrate is segmented into multiple isolated potential regions through the introduction of insulating layers and conductive isolation structures. Each GaN device can be assigned to a specific substrate region with its own independent potential control, preventing substrate potential interference between devices while maintaining simplified integration architecture.
Solution Approach 2:
Insulating layers and conductive isolation structures are introduced as intermediary elements between the substrate and GaN devices. These intermediaries enable independent potential control of substrate regions, blocking harmful substrate potential propagation while maintaining electrical connectivity where needed.
2Reliability
If the substrate potential is controlled to prevent device turn-on, then device reliability improves, but heat dissipation from the substrate becomes less effective
Solution Approach 1:
Different regions of the substrate are assigned different functional qualities: regions under active GaN devices are provided with independent potential control through insulating layers and conductive structures to prevent device turn-on, while other substrate regions maintain direct electrical connectivity for effective heat dissipation. This local differentiation resolves the contradiction between reliability and thermal management.
3Reliability
If insulating layers are added to isolate substrate regions for independent potential control, then substrate potential interference is eliminated, but device structure complexity increases
Solution Approach 1:
The insulating layers and conductive isolation structures are designed to serve multiple functions simultaneously: they provide electrical isolation for independent potential control, define device active regions, and can be integrated with existing fabrication processes. This multi-functionality reduces the net increase in device structure complexity while achieving reliable substrate potential control.
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 independent control of substrate potentials under each contact within a semiconductor device, improving operational reliability and heat management, allowing for optimal performance in high-frequency and high-voltage applications while preventing undesirable voltage effects.
Implementation Method 1
The implementation of implanted wells or diffused conductive regions, combined with via connections, allows for the electrical isolation of substrate regions from each other
Implementation Method 2
The different interior layers have different band gaps, which causes polarization that contributes to a conductive two-dimensional electron gas (2DEG) region near the junction of the two layers
Data Source
AI summary
Circuits, structures and techniques for independently connecting a surrounding material in a part of a semiconductor device to a contact of its respective device. To achieve this, a combination of one or more conductive wells that are electrically isolated in at least one bias polarity are provided.