Integrated Isolating Switch With Pinch-Off Channels for Low-Loss Shutdown
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Solution Overview
Problem
Existing semiconductor switches struggle to efficiently manage high operating voltages while maintaining low on-state losses and enabling rapid automatic shutdown during overcurrents, with limitations in blocking mode and high on-resistance issues.
Innovation Solution
A monolithically integrated semiconductor switch with n-doped channels forming a current-dependent series resistor between the n-doped contact region and the source or emitter region of a field effect transistor, which pinches off at high currents, and p-doped regions providing additional current-carrying capacity through ohmic connections, allowing for high blocking voltages and rapid switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If semiconductor switches are used to achieve rapid switching and low on-state losses, then switching speed and efficiency are improved, but blocking capability at high voltages deteriorates
Solution Approach 1:
The patent changes the doping parameters of the semiconductor regions, specifically using a first doping concentration for the drift region and a second, higher doping concentration for the extension region. This parameter change enables the extension region to provide additional blocking capability at high voltages while the drift region maintains low on-resistance for efficient conduction, thus resolving the contradiction between switching speed and blocking capability.
2Loss of energy
If higher doping concentrations are used to reduce on-resistance and lower on-state losses, then conduction efficiency is improved, but blocking voltage capability deteriorates
Solution Approach 1:
The patent segments the drift region into two distinct doped regions: a first drift region with lower doping concentration for maintaining low on-resistance during conduction, and a second drift region (extension region) with higher doping concentration for providing blocking capability at high voltages. This segmentation allows each region to optimize its function independently, reducing on-state losses while maintaining blocking voltage capability.
Solution Approach 2:
The patent applies local quality by creating regions with different doping concentrations in specific locations. The extension region with higher doping concentration is locally positioned in the drift region to provide enhanced blocking capability where needed, while the main drift region maintains lower doping concentration for low on-resistance conduction, thus achieving both low on-state losses and high blocking voltage capability.
3Device complexity
If monolithic integration is used to reduce device complexity and improve compactness, then manufacturing simplicity and space utilization are improved, but achieving high voltage blocking with low on-resistance deteriorates
Solution Approach 1:
The patent merges multiple functions into a single monolithically integrated semiconductor device. The n-channel JFET provides switching functionality, while the drift region with its two doped regions provides both conduction path and voltage blocking capability. This merging of functions into one integrated structure reduces device complexity and eliminates the need for separate components, while the carefully designed doping profile ensures low on-resistance during conduction.
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 design achieves low on-state losses during normal operation and rapid switching off at high currents, suitable for high-voltage applications with reduced complexity and energy consumption, enhancing reliability and efficiency.
Implementation Method 1
n-doped channels forming a current-dependent series resistor between the n-doped contact region and the source or emitter region of a field effect transistor, which pinches off at high currents
Implementation Method 2
p-doped regions providing additional current-carrying capacity through ohmic connections
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
In a semiconductor switch with a monolithically integrated field-effect transistor, the source or emitter region (15) of the field-effect transistor is connected to a first electrical terminal (10, K) via a semiconductor region (11) and an n-doped contact region (18). Within the semiconductor region (11), a semiconductor structure with n-doped channels (19) is formed between the n-doped contact region (18) and the source or emitter region (15) of the field-effect transistor. These channels electrically connect the n-doped contact region (18) to the source or emitter region (15) of the field-effect transistor and extend between p-doped regions (20) that are connected to the n-doped contact region (18). The semiconductor switch is suitable as a self-switching load break switch and exhibits low losses in the switched-on state.