Bootstrap Diode Structure for Pinch-Off and Leakage Control
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Solution Overview
Problem
Existing bootstrap diodes and Junction Field Effect Transistors (JFETs) face challenges in achieving various pinch-off voltages and low-level leakage currents, making it difficult to meet customer demands.
Innovation Solution
A semiconductor device with specific deep well regions, pinch-off regions, and buried layers is designed to control pinch-off voltage and forward current by varying the depth and doping concentration of the pinch-off region, and includes a laterally-diffused metal-oxide semiconductor (LDMOS) for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the N-type source region of the JFET is replaced by a P-type source region to obtain the Bootstrap diode structure, then the device can function as a bootstrap diode, but it becomes challenging to achieve various pinch-off voltages and low-level leakage currents
Solution Approach 1:
The patent introduces a pinch-off region with specific doping concentration (less than the deep well regions) and a groove or dip at its bottom surface, creating localized structural variations. This allows different regions of the device to have different electrical characteristics, enabling precise control of pinch-off voltage and leakage current while maintaining the bootstrap diode function
Solution Approach 2:
The patent adds a vertical dimension feature by introducing a groove or dip at the bottom surface of the pinch-off region. This three-dimensional structural modification allows for better control of the electric field distribution and charge carrier flow, enabling simultaneous achievement of various pinch-off voltages and low leakage currents
2Adaptability or versatility
If deep well regions with different lengths are used to control pinch-off voltage, then various pinch-off voltages can be achieved, but the device structure becomes more complex
Solution Approach 1:
The patent controls pinch-off voltage by varying the depth and doping concentration of the pinch-off region relative to the deep well regions. By adjusting these parameters (depth, doping concentration), different pinch-off voltages can be achieved without fundamentally changing the overall device structure, thus reducing complexity while maintaining versatility
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 solution enables precise control of pinch-off voltage and forward current, reducing leakage current and enhancing breakdown voltage, thus improving the performance and manufacturability of bootstrap diodes.
Implementation Method 1
the N-type sink region is configured to have a doping concentration higher than a doping concentration of the first deep well region
Implementation Method 2
the pinch-off region is disposed between the first deep well region and the second deep well region and is configured to have a depth smaller than depths of the first deep well region and the second deep well region from a top surface of the substrate
Data Source
AI summary
A semiconductor device including a bootstrap diode is provided. The semiconductor device comprises a first deep well region and a second deep well region disposed in a substrate; a pinch-off region disposed between the first and second deep well regions and configured to have a depth smaller than depths of the first and second deep well regions from a top surface of a substrate; a first buried layer and a second buried layer respectively disposed in the first and second deep well regions; a P-type source region and a N-type drain region respectively disposed in the first and second deep well regions; and a N-type sink region surrounding the P-type source region, where the N-type sink region has a doping concentration higher than a doping concentration of the first deep well region.