ESD Protection Element With Surrounded Diffusion Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor integrated circuit devices face a trade-off between reduced input capacitance and high resistance to electrostatic discharge (ESD) as the integration level increases, with conventional ESD protection elements influencing high-speed interface waveforms and compromising surge protection.
Innovation Solution
A semiconductor integrated circuit device with an ESD protection element configuration where a first diffusion layer is surrounded by a second diffusion layer of opposite conductivity type, increasing the facing length to enhance surge discharge capability while reducing input capacitance, and incorporating dielectric isolation regions to prevent PN junction formation and surge current concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the area of the diffusion layer is reduced to reduce input capacitance, then the capacitance is reduced, but the ability to discharge surge is reduced
Solution Approach 1:
The patent transitions from a conventional planar diffusion layer structure to a three-dimensional surrounded structure where a first diffusion layer is enclosed by a second diffusion layer of opposite conductivity type. This dimensional change increases the effective discharge path length and surface area for surge dissipation without increasing the planar footprint, thereby reducing input capacitance while maintaining or enhancing surge discharge capability.
Solution Approach 2:
The patent implements a nested configuration where the first diffusion layer is surrounded by the second diffusion layer, creating a concentric structure. This nesting allows the inner diffusion layer to maintain small area (low capacitance) while the outer diffusion layer provides extended discharge pathways and increased effective area for surge handling, resolving the contradiction between small capacitance and high surge resistance.
2Reliability
If a protection element is formed for high-speed interface, then surge protection is provided, but the protection element influences the waveform of transfer data
Solution Approach 1:
The patent modifies the physical and electrical parameters of the protection element by creating a surrounded diffusion layer structure with controlled conductivity types and proportions. This parameter optimization reduces the input capacitance and discharge resistance values, allowing the protection element to operate with minimal impact on high-speed signal waveforms while maintaining effective surge protection capability.
3Reliability
If the facing length is increased to enhance surge discharge capability, then the discharge capability is improved, but the area increases
Solution Approach 1:
The patent resolves this contradiction by utilizing vertical and radial dimensions through the surrounded diffusion layer configuration. The facing length is extended in three-dimensional space rather than purely in the planar direction, allowing increased discharge capability while maintaining compact planar area. The nested structure enables longer discharge paths without proportional area increase.
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 configuration achieves reduced input capacitance and high resistance to ESD, effectively protecting high-speed interfaces from surge damage and preventing latch-up with improved reliability.
Implementation Method 1
a diode including: a well region of a first conductivity type in a semiconductor substrate; and a first diffusion layer of a second conductivity type in the well region
Implementation Method 2
Upon intrusion of a surge via the pad 123 for external connection, a diode formed by the well region 110 and the diffusion layer 111 is brought into conduction
Implementation Method 3
The diffusion layer 111 and the diffusion layer 112 are arranged facing each other with a dielectric isolation region 113 interposed therebetween
Data Source
AI summary
An electro static discharge protection element being formed by a diode including a well region of a first conductivity type on a surface of a semiconductor substrate, and a first diffusion layer of a second conductivity type in the well region. The first diffusion layer is surrounded by a second diffusion layer of the first conductivity type in the well region. The first diffusion layer has a surface on which a first contact region connected to an input/output terminal is formed. The first diffusion layer has a surface on which a second contact region connected to a reference voltage terminal is formed.