ESD Clamping Device Leakage Reduction via Segmented Implantation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ESD clamping devices for semiconductor devices suffer from high leakage currents during normal operation due to p-type ESD implantations, which reduce the reverse junction breakdown voltage, making them unsuitable for low leakage applications.
Innovation Solution
The design incorporates a size-reduced ESD implantation region and additional heavily doped regions to form an ESD gated diode, which minimizes leakage current during normal operation and ensures early triggering during ESD events, enhancing turn-on efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If p-type ESD implantation is used to enhance ESD robustness, then ESD protection capability is improved, but reverse junction breakdown voltage is reduced to 6V-7V causing excessive leakage current during normal operation
Solution Approach 1:
The drain region is segmented into multiple lightly-doped drain (LDD) regions with different doping concentrations and depths. This segmentation allows the device to maintain low leakage current during normal operation while providing sufficient ESD protection when needed.
Solution Approach 2:
Different regions of the drain are given different local qualities through selective ESD implantation. The ESD implantation is applied selectively to certain LDD regions to create areas with enhanced ESD robustness while other regions maintain low leakage characteristics.
2Reliability
If reverse junction breakdown voltage is reduced to enable early turn-on of parasitic bipolar transistor, then ESD turn-on efficiency is improved, but leakage current during normal operation becomes excessively large
Solution Approach 1:
The doping concentration and depth parameters of the LDD regions are carefully controlled to achieve the desired balance. By adjusting these parameters, the device maintains an appropriate reverse junction breakdown voltage that enables early turn-on during ESD events while minimizing leakage during normal operation.
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
This configuration effectively reduces standby leakage current and improves ESD protection efficiency, making it suitable for low leakage current applications by allowing the ESD gated diode to turn on first during ESD events and provide driving current for early triggering.
Implementation Method 1
the ESD implantation region being a heavily doped region of said second conductivity type
Data Source
AI summary
An ESD clamping device comprises a plurality of fingers each comprising a source region of first conductivity type formed in a substrate of second conductivity type, a drain region of said first conductivity type formed in the substrate, and a gate formed over the substrate and between the source and drain regions. At least one of the fingers each has an ESD implantation region formed in the substrate and partially underlying the drain region of the finger, the ESD implantation region being a heavily doped region of said second conductivity type. Furthermore, at least one of the fingers has a gate extension portion projecting from the gate and demarcating an additional region in at least the drain region of the finger, the additional region of said second conductivity type being electrically connected to at least one of the gate and the substrate of each of the fingers.