Semiconductor Diode With Asymmetric Holes for ESD Protection
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Solution Overview
Problem
High-brightness LEDs are sensitive to electrostatic discharges due to their substrate material, leading to potential catastrophic failures, and existing ESD protection methods like Zener diodes increase complexity and cost, necessitating a more efficient and cost-effective solution for ESD protection.
Innovation Solution
A semiconductor device with a diode structure featuring holes or trenches of varying widths and depths, where the inner walls are doped oppositely to the substrate, allowing for improved current distribution and increased current sustain, enabling effective bi-directional ESD protection while minimizing size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Zener diodes are used for ESD protection, then ESD robustness is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple ESD protection functions into a single integrated diode structure with multiple holes/trenches formed in the semiconductor substrate. This integrated approach eliminates the need for separate Zener diodes and capacitors, reducing device complexity while maintaining ESD robustness through the collaborative operation of multiple holes within one device
Solution Approach 2:
The diode is segmented into multiple holes or trenches (at least two) with different widths and depths, each contributing to the overall ESD protection capability. This segmentation allows the current to be distributed across multiple paths, enhancing ESD robustness while keeping the overall device structure compact and simple
2Device complexity
If Zener diode size is reduced to lower cost, then cost decreases, but ESD robustness deteriorates
Solution Approach 1:
Different holes or trenches within the diode have different local qualities - specifically different widths and depths. This allows each region to contribute differently to the ESD protection, with larger holes handling higher current densities and smaller holes providing additional protection paths, achieving high ESD robustness in a compact area
Solution Approach 2:
The invention transitions from a two-dimensional planar diode structure to a three-dimensional structure with holes of varying depths. This vertical dimensionality addition allows increased P/N junction area and current sustain capability without increasing the lateral footprint, thereby maintaining cost-effectiveness while improving ESD robustness
3Ease of manufacture
If multiple holes with same dimensions are used, then manufacturing is simplified, but current sustain is limited
Solution Approach 1:
The patent implements local quality by making each hole or trench have different width and/or depth dimensions. This variation in local geometry creates different current handling capacities across the structure, with larger holes sustaining higher currents and smaller holes providing additional protection, collectively achieving superior current sustain capability
Solution Approach 2:
The diode structure employs asymmetry by deliberately designing holes with non-uniform dimensions rather than identical repeating units. This asymmetric configuration optimizes current distribution and sustain capability, with the largest holes positioned to handle the majority of ESD current while smaller holes provide supplementary protection paths
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 proposed diode structure enhances ESD robustness by increasing current sustain and reducing leakage, achieving 20% higher TLP current capacity compared to prior art designs with similar footprint, while optimizing integration and reducing overheating.
Implementation Method 1
the inner wall of each hole is doped so that its doping is from the other type than the doping of the substrate
Implementation Method 2
Electrostatic discharges and electrostatic damages can occur at any point from manufacture to field service
Data Source
AI summary
A semiconductor device comprising at least two holes (18, 20) realized in a substrate (6), having each a width and a depth, and forming a diode (4), wherein the substrate (6) has a determined type of doping, wherein the inner wall of each hole (18, 20) is doped so that its doping is of the other type than the doping of the substrate (6), and wherein the width and/or the depth of a hole (18, 20) is different from the width and/or the depth of a neighboring hole.