Semiconductor ESD Protection Using Segmented PN Junction Diodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional semiconductor devices face challenges in effectively protecting against electrostatic discharge (ESD) due to increased impedance in miniaturized components, leading to breakdown and potential damage within internal circuits, particularly in devices requiring lower voltage operations like mobile phones, where existing ESD protection elements fail to manage static electricity discharge efficiently.
Innovation Solution
A semiconductor device structure incorporating a PN junction diode and parasitic bipolar transistors, with specific buried and diffusion layers configured to form an ESD protection element, allowing for controlled breakdown and enhanced discharge current flow, thereby protecting internal circuits from static electricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If miniaturization of elements is enhanced for higher speed, then processing speed is improved, but electrostatic breakdown tolerance decreases
Solution Approach 1:
The ESD protection element is segmented into multiple functional regions: a first region with high impurity concentration for low breakdown voltage, and a second region with low impurity concentration for high breakdown voltage. This segmentation allows the device to provide effective ESD protection for miniaturized circuits while maintaining appropriate voltage characteristics for different operational conditions.
Solution Approach 2:
Different regions of the ESD protection element are assigned different impurity concentrations to create local quality variations. The first region has high impurity concentration to provide low breakdown voltage for immediate ESD protection, while the second region has low impurity concentration to maintain high breakdown voltage and prevent interference with normal circuit operation. This local quality differentiation resolves the contradiction between speed enhancement and electrostatic tolerance.
2Volume of moving object
If conventional ESD protection elements are used in miniaturized devices, then device size is reduced, but discharge path impedance increases
Solution Approach 1:
The discharge path is segmented into two regions with different impurity concentrations. The first region provides a low-impedance path for ESD current discharge, while the second region maintains high impedance for normal operation. This segmentation enables effective ESD protection in miniaturized devices without increasing overall discharge path impedance.
Solution Approach 2:
The impurity concentration parameter is changed spatially within the ESD protection element. The first region uses high impurity concentration to reduce discharge path impedance for ESD currents, while the second region uses low impurity concentration to maintain normal operational characteristics. This parameter change enables effective ESD protection in compact device sizes.
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 semiconductor device achieves high ESD protection characteristics by setting a desired breakdown voltage for the PN junction diode and utilizing parasitic bipolar transistors to manage discharge currents effectively, ensuring immediate protection and enhanced heat radiation, even at lower voltage operations.
Implementation Method 1
When a positive voltage by static electricity is applied from the power supply line 51 to the collector of the NPN bipolar transistor 57 connected to the power supply line 51 and a negative voltage is applied from the ground line 53 to the emitter connected to the ground line 53, the NPN bipolar transistor 57 breaks down at the time when the voltage reaches a collector-emitter breakdown voltage BVCER or more
Implementation Method 2
a discharge path of static electricity occurs through some junction in the internal circuit 56, thereby causing a problem of breaking the junction in the internal circuit 56
Data Source
AI summary
An ESD protection element is formed by a PN junction diode including an N+ type buried layer having a proper impurity concentration and a P+ type buried layer and a parasitic PNP bipolar transistor which uses a P+ type drawing layer connected to a P+ type diffusion layer as the emitter, an N− type epitaxial layer as the base, and a P type semiconductor substrate as the collector. The P+ type buried layer is connected to an anode electrode, and the P+ type diffusion layer and an N+ type diffusion layer connected to and surrounding the P+ type diffusion layer are connected to a cathode electrode. When a large positive static electricity is applied to the cathode electrode, the parasitic PNP bipolar transistor turns on to flow a large discharge current.