High Voltage Device Air Layer Breakdown Voltage
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Solution Overview
Problem
High voltage devices, such as flyback diodes and LIGBTs, on silicon-on-insulator (SOI) substrates face limitations in breakdown voltage and heat dissipation due to strong heat accumulation, leading to increased power loss and reduced efficiency.
Innovation Solution
Incorporating an air layer in the insulation of high voltage devices on partial SOI substrates, positioned under a deep well and spaced apart from the substrate, which alters the electrical field to increase breakdown voltage and facilitates heat dissipation by communicating with the atmosphere.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If high voltage devices are formed on SOI process, then integration and control are improved, but breakdown voltage is restricted by oxide thickness and top silicon thickness
Solution Approach 1:
The patent introduces a vertical air gap dimension between the deep well and substrate, creating a three-dimensional field modulation structure. This additional spatial dimension allows the electrical field to be shaped and extended vertically, enabling higher breakdown voltage without increasing lateral device complexity or changing oxide/thin-film thickness parameters.
Solution Approach 2:
The patent changes the physical structure by introducing an air gap with specific height (e.g., 1-10 micrometers), transforming the electrical field distribution parameters. This geometric parameter change modifies the field concentration and voltage breakdown characteristics, allowing optimization of breakdown voltage independent of oxide thickness constraints.
2Ease of operation
If high voltage devices are formed on SOI process, then control characteristics are improved, but heat accumulation increases leading to power loss
Solution Approach 1:
The patent extracts heat from the device structure by introducing air gaps that serve as thermal conduction pathways to the substrate. The air layer, while electrically isolating, provides thermal coupling to conduct heat away from the active device regions, separating thermal management from electrical isolation functions.
Solution Approach 2:
The air gap acts as an intermediary layer between the deep well and substrate, serving dual functions: electrically isolating the high voltage node while thermally coupling to facilitate heat dissipation. This intermediary structure mediates between electrical performance requirements and thermal management needs.
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 effectively enhances the electrical performance of high voltage devices by increasing breakdown voltage and improving heat dissipation, addressing the issues of low breakdown voltage and heat accumulation.
Implementation Method 1
the electrical field of the HV device can be altered for increasing the breakdown voltage of the HV devices
Implementation Method 2
the air layer also communicates with an atmosphere outside the HV device, which facilitates heat dissipation
Data Source
AI summary
A high voltage (HV) device and method for manufacturing the same are provided, at least comprising a substrate, an insulation formed on the substrate, a deep well formed in the insulation, an air layer formed in the insulation and disposed adjacent to the bottom surface of the deep well. A bottom surface of the deep well is spaced apart from the substrate. Also, the air layer, interposed between the deep well and the substrate, is spaced apart from the substrate. In one embodiment, an air layer further communicates with an atmosphere outside the HV device, which facilitates heat dissipation.