BJT-NFET ESD Protection Circuit for Uniform Current Sharing
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Solution Overview
Problem
As semiconductor processes advance, integrated circuits face challenges in electrostatic discharge (ESD) protection due to reduced element sizes, lower operating voltages, and increased signal frequencies, leading to inadequate ESD protection and potential damage from concentrated currents in parallel circuits.
Innovation Solution
A device incorporating a bipolar junction transistor (BJT) and n-channel field effect transistors (NFETs) connected in parallel, with resistors and diodes, provides a low-impedance discharge path and ballistic resistance to distribute ESD currents uniformly, ensuring high reliability and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If parallel circuits are used to provide ESD protection, then current driving capability is improved, but current concentration occurs leading to potential damage
Solution Approach 1:
The patent divides the ESD protection function into multiple parallel circuits, each handling a portion of the ESD current. By segmenting the current path into multiple independent branches, the total ESD current is distributed across several circuits rather than concentrating in a single path, thereby maintaining high current driving capability while preventing current concentration damage.
Solution Approach 2:
The patent introduces local resistance elements at specific locations within each parallel circuit branch. These localized resistive components create voltage drops that actively regulate and balance the current distribution across different branches, ensuring uniform current sharing and preventing any single circuit from bearing excessive current stress.
2Area of stationary object
If element sizes are reduced to achieve high integration, then device area is reduced, but ESD protection capability deteriorates
Solution Approach 1:
The patent transitions from planar two-dimensional layout to three-dimensional vertical structure by stacking multiple ESD protection circuits in the vertical dimension. This allows multiple functional layers to be integrated within a compact footprint, achieving high ESD protection capability without proportionally increasing the device area, as the circuits utilize the vertical space above the substrate.
Solution Approach 2:
The patent implements nested structures where smaller ESD protection circuits are embedded within or alongside larger circuit blocks. The ESD protection elements are strategically positioned and integrated into the existing circuit architecture, allowing compact nesting of protection functions within the overall device layout to maximize area efficiency.
3Use of energy by moving object
If operating voltage is reduced to lower power consumption, then power consumption is reduced, but ESD protection efficiency deteriorates
Solution Approach 1:
The patent utilizes parameter changes in the electrical characteristics of the ESD protection circuits, specifically designing circuits with voltage-dependent resistance properties. At normal low operating voltages, the circuits maintain high impedance to minimize power consumption, but when ESD events occur with high voltage spikes, the impedance automatically decreases to provide efficient current discharge paths, thus achieving both low power consumption and high ESD protection efficiency.
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 effectively protects integrated circuits from ESD by distributing currents uniformly, preventing concentration and enhancing reliability and robustness, even under stringent requirements of high current driving capability and low triggering voltage.
Implementation Method 1
Electrostatic discharge (ESD) may cause an integrated circuit to malfunction, or may even damage the integrated circuit
Data Source
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AI summary
Provided is a device including a first well having a first conductivity type, a first gate electrode on the first well, a first region and a second region each having a second conductivity type on the first well with the first gate electrode disposed therebetween, a third region having the second conductivity type on the first well, and a fourth region having the first conductivity type on the first well. The first gate electrode and the first region are electrically connected to a first node, and the third region is electrically connected to a second node.