Protection Diode End Face Exposure for ESD Immunity
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Solution Overview
Problem
Conventional ESD protection diodes in semiconductor devices have ineffective surface areas due to their ring-like closed annular structure, leading to increased surface area and reduced ESD immunity when attempting to enhance junction surface area for better protection.
Innovation Solution
The semiconductor device incorporates a semiconductor region with a band configuration of N-type and P-type semiconductor regions forming protection diodes in an NPNPN structure, with electrodes connected to the N-type regions, ensuring that the PN junctions are exposed at the end face, allowing for effective breakdown and current flow while minimizing ineffective surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the junction surface area of a protection diode is increased to obtain high ESD immunity, then the ESD immunity is improved, but the ineffective surface area increases and the surface area of the entire device increases
Solution Approach 1:
The patent transitions from a two-dimensional planar ring-like structure to a three-dimensional structure by exposing the PN junction at the end face of the semiconductor region. This vertical exposure allows the junction surface area to be increased without proportionally increasing the planar footprint, thereby improving ESD immunity while minimizing the ineffective surface area and overall device area.
2Ease of manufacture
If a ring-like closed annular structure is used for protection diode, then the manufacturing process has high degrees of freedom, but the central portion surface area becomes ineffective
Solution Approach 1:
The patent extracts the PN junction from the enclosed ring structure and exposes it at the end face of the semiconductor region. This extraction eliminates the ineffective central portion inherent in ring-like structures while maintaining the manufacturing flexibility of forming the semiconductor region as a protective layer over the substrate. The junction is now accessible and functional across the entire exposed end face area.
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 configuration achieves high ESD immunity with a low ineffective surface area, preventing radical current concentration and diode deterioration, thus enhancing the protection diode's functionality and manufacturing efficiency.
Implementation Method 1
An overvoltage causes breakdown of the protection diode. A PN junction of the protection diode is exposed at an end face of the semiconductor region.
Data Source
AI summary
According to one embodiment, a semiconductor device includes a semiconductor substrate, a semiconductor region, a first and second electrodes. The semiconductor region is provided on the semiconductor substrate via an insulating film. The semiconductor region includes a protection diode. An overvoltage causes breakdown of the protection diode. A PN junction of the protection diode is exposed at an end face of the semiconductor region. A first and second electrodes are provided distally to the exposed end face of the PN junction. The first and second electrodes are connected to the semiconductor region to provide a current to the protection diode.