ESD Protection Structure with Optical Triggering
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Solution Overview
Problem
Existing ESD protection structures in integrated circuits face challenges in meeting stringent requirements for rapid reaction time and high robustness, particularly at the system level, due to delays in avalanche breakdown triggering, leading to potential voltage overshoots and hazards for circuit protection.
Innovation Solution
An integrated circuit design that incorporates an ESD protection structure electrically and optically coupled with a photon source, allowing photons emitted during ESD loading to initiate avalanche breakdown, thereby preventing delays and ensuring effective discharge current dissipation without triggering at voltage differences between +10 V and -10 V.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ESD protection structures are used, then the circuit block is protected against electrostatic discharge, but the reaction time is delayed due to avalanche breakdown triggering delays
Solution Approach 1:
The patent applies preliminary action by pre-biasing the ESD protection structure through a photon source that is forward-biased during normal operation. This pre-biasing stores energy and prepares the structure for rapid response. When ESD occurs, the stored energy immediately triggers avalanche breakdown without delay, achieving sub-nanosecond response times while maintaining reliable protection
2Loss of time
If ESD protection structures are designed for rapid reaction, then the reaction time is reduced, but the robustness against high peak currents is compromised
Solution Approach 1:
The patent merges two previously separate functions into a single integrated structure: the photon source and the ESD protection diode are combined in a shared semiconductor region. This integration allows the structure to simultaneously achieve rapid response (through optical triggering) and high robustness (through the inherent current-handling capability of the merged device), enabling sub-nanosecond reaction times while withstanding peak currents above 6 amperes
3Strength
If the ESD protection structure is made more robust, then the peak current handling is improved, but the leakage current increases
Solution Approach 1:
The patent applies dynamics by making the ESD protection structure's electrical characteristics dynamically controllable through optical triggering. During normal operation, the structure maintains low leakage current by remaining in a high-impedance state. When photons from the forward-biased source trigger avalanche breakdown, the structure dynamically switches to a low-impedance state capable of handling high peak currents, thus achieving both low static power consumption and high dynamic robustness
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 rapid and reliable protection against electrostatic discharges, reducing voltage overshoots and ensuring the circuit section is protected without additional leakage current or area expenditure, meeting stringent system-level ESD standards.
Implementation Method 1
photons emitted by the photon source upon ESD loading are absorbable in the ESD protection structure and an avalanche breakdown is initiatable by electron-hole pairs generated by the absorbed photons
Implementation Method 2
an avalanche breakdown is initiatable by electron-hole pairs generated by the absorbed photons
Data Source
AI summary
An integrated circuit having an ESD protection structure is described. One embodiment includes a circuit section interconnected with a first terminal and with a second terminal and being operable at voltage differences between the first terminal and second terminal of greater than +10 V and less than −10 V. The integrated circuit additionally includes an ESD protection structure operable to protect the circuit section against electrostatic discharge between the first terminal and the second terminal. The ESD protection structure is operable with voltage differences between the first and second terminals of greater than +10 V and less than −10 V without triggering. The ESD protection structure is electrically and optically coupled to a photon source such that photons emitted by the photon source upon ESD pulse loading are absorbable in the ESD protection structure and an avalanche breakdown is initiatable by electron-hole pairs generated by the absorbed photons.