Flip-Chip LED Chip with Integrated Reverse-Parallel Diode for ESD Protection
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Solution Overview
Problem
Existing light emitting diode (LED) technologies face challenges with electrostatic discharge (ESD) protection, particularly in high-brightness LED applications, where crystal defects in GaN-based semiconductors on sapphire substrates lead to breakdown under high voltage, and traditional ESD protection methods like Zener diodes are costly and reduce luminous efficacy.
Innovation Solution
A flip-chip type light emitting diode chip design incorporating a reverse-parallel diode part connected to the light emitting diode part, with conductive nitride-based semiconductor layers and an active layer, provides ESD protection by dispersing current through a current dispersion layer and using electrode pads to connect the diodes, eliminating the need for separate ESD protection devices like Zener diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional ESD protection devices like Zener diodes are used, then ESD protection is provided, but manufacturing cost increases and luminous efficacy decreases
Solution Approach 1:
The patent combines the ESD protection function with the LED chip structure itself by integrating a reverse-parallel diode configuration directly into the chip. This merging eliminates the need for separate Zener diode components, thereby maintaining luminous efficacy while providing ESD protection through the integrated diode structure that shunts ESD current away from sensitive regions.
Solution Approach 2:
The LED chip structure is designed to perform multiple functions: light emission through the active layer and ESD protection through the reverse-parallel diode configuration. This multi-functionality allows the same chip structure to serve both as the light-generating element and as the ESD protection mechanism, eliminating the need for additional dedicated ESD protection components that would reduce luminous efficacy.
2Reliability
If traditional ESD protection devices like Zener diodes are used, then ESD protection is provided, but manufacturing cost increases
Solution Approach 1:
The ESD protection function is merged into the LED chip fabrication process itself. The reverse-parallel diode structure is created using the same epitaxial growth and processing steps as the LED chip, eliminating the need for separate Zener diode components and their associated mounting, wiring, and assembly operations. This integration significantly reduces manufacturing cost while maintaining ESD protection capability.
Solution Approach 2:
The patent extracts the ESD protection function from separate external components (Zener diodes) and embeds it directly into the LED chip structure. By taking out the need for external ESD protection devices and integrating the protection function into the chip itself, the manufacturing process is simplified and costs are reduced.
3Power
If high voltage is applied to epitaxial layers with crystal defects, then current is concentrated on defects, but breakdown of diode is promoted
Solution Approach 1:
The reverse-parallel diode acts as an intermediary path for ESD current. When high voltage ESD occurs, the reverse-parallel diode provides a low-resistance shunt path that diverts the harmful current away from the sensitive active layer and crystal defects, preventing breakdown while allowing the LED to operate at high voltages normally.
Solution Approach 2:
The patent converts the harmful effect of high-voltage ESD current into a beneficial protective mechanism. The reverse-parallel diode configuration is designed to conduct heavily under reverse bias conditions, effectively using the harmful ESD current to trigger the protection mechanism that shunts the current away from sensitive regions, thereby converting the harmful high-voltage event into a self-protecting response.
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 design significantly enhances the LED chip's resistance to ESD, maintaining high luminous efficacy and simplifying the manufacturing process by integrating ESD protection within the chip structure, thereby reducing yield loss and manufacturing costs.
Implementation Method 1
A flip-chip type light emitting diode chip is provided to include: a substrate; a light emitting diode part aligned on the substrate; and a reverse-parallel diode part disposed on the substrate and connected to the light emitting diode part. The light emitting diode part can be protected from electrostatic discharge by the reverse-parallel diode part.
Data Source
AI summary
Disclosed herein is a light emitting diode chip having ESD protection. An exemplary embodiment provides a flip-chip type light emitting diode chip, which includes a light emitting diode part aligned on a substrate, and a reverse-parallel diode part disposed on the substrate and connected to the light emitting diode part. Within the flip-chip type light emitting diode chip, the light emitting diode part is placed together with reverse-parallel diode part, thereby providing a light emitting diode chip exhibiting strong resistance to electrostatic discharge.