Tapered Recess TVS Diode for Low Voltage Transient Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional TVS junction diodes have high breakdown voltages, making them inadequate for low voltage applications, such as devices operating at 3 volts or lower, where reducing the breakdown voltage is necessary to effectively clamp transient voltages.
Innovation Solution
A semiconductor junction device with a tapered recess, such as a V-groove, is created in a low resistivity semiconductor substrate, enhancing the local electrical field and increasing current density, thereby reducing the breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TVS junction diodes are used, then high breakdown voltage is achieved, but low voltage applications cannot be protected
Solution Approach 1:
The patent applies local quality by creating a tapered recess structure at the junction interface to concentrate the electric field locally. This localized field enhancement allows the breakdown voltage to be reduced specifically at the junction region without requiring the entire device structure to be modified, enabling low voltage protection while maintaining overall device integrity
Solution Approach 2:
The patent introduces a vertical dimension by etching a tapered recess into the substrate, transforming the traditional planar junction into a three-dimensional structure. This dimensional change creates a concentrated electric field region at the bottom of the recess, enabling breakdown voltage reduction for low voltage applications
2Reliability
If breakdown voltage is reduced for low voltage applications, then transient suppression is effective, but device structure becomes more complex
Solution Approach 1:
The patent segments the device structure by separating the junction formation into distinct regions: a tapered recess region for field concentration and a surrounding planar region. This segmentation allows the complex low voltage junction to be integrated with standard planar processing techniques, reducing overall manufacturing 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
The enhanced local electrical field and current density in the semiconductor junction device result in a lower breakdown voltage, effectively suppressing transient voltages in low voltage applications.
Implementation Method 1
enhancing the local electrical field and increasing current density
Implementation Method 2
A tapered recess extends into the substrate and tapers inward as it extends downward from an upper surface of the substrate
Implementation Method 3
the reverse bias voltage exceeds the reverse breakdown voltage and the TVS junction diode clamps the transient voltage to be equal to the reverse breakdown voltage of the diode
Data Source
AI summary
A semiconductor junction device includes a substrate of low resistivity semiconductor material having a preselected polarity. A tapered recess extends into the substrate and tapers inward as it extends downward from an upper surface of the substrate. A semiconductor layer is disposed within the recess and extends above the upper surface of the substrate. The semiconductor layer has a polarity opposite from that of the substrate. A metal layer overlies the semiconductor layer.