ESD Diode EPI Block Reduces Leakage and Boosts Voltage Rating
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Solution Overview
Problem
Semiconductor devices, particularly FinFETs, are susceptible to high voltage spikes such as electrostatic discharge (ESD) that can cause device failure, and existing ESD protection structures are not adequately effective in reducing leakage current and improving voltage rating.
Innovation Solution
The use of EPI block regions in n-type and p-type ESD protection diodes, formed through an epitaxial growth process, reduces the size and improves the overdrive capability of ESD protection diodes, enhancing their voltage rating and providing a more efficient current discharge path during ESD events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ESD protection structures are used, then ESD protection is provided, but leakage current is not adequately reduced and voltage rating is limited
Solution Approach 1:
The patent applies local quality by creating EPI block regions with different material properties (epitaxially grown semiconductor material) in specific locations between the N+ and P+ regions. These localized regions have different electrical characteristics compared to the surrounding material, providing enhanced ESD protection and reduced leakage current in critical areas while maintaining normal device operation elsewhere.
Solution Approach 2:
The patent uses composite materials by combining conventional semiconductor regions (N+ and P+ doped regions) with EPI block regions (epitaxially grown semiconductor material) to create a hybrid structure. This composite approach leverages the beneficial properties of both material types: the high doping concentration regions for charge injection and the epitaxial regions for controlled electrical properties and leakage reduction.
2Reliability
If ESD protection diodes are made larger to improve voltage rating, then voltage rating increases, but device area increases
Solution Approach 1:
The patent applies parameter changes by modifying the electrical properties of the semiconductor structure through the introduction of EPI block regions. These regions change key parameters such as breakdown voltage, leakage current, and charge storage capacity without requiring proportional increases in physical dimensions. The epitaxial growth process allows precise control of material properties, enabling high voltage rating in a compact area.
3Reliability
If EPI block regions are added to ESD protection diodes, then voltage rating and overdrive capability improve, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the ESD protection diode into distinct functional regions: N+ regions for electron injection, P+ regions for hole injection, and EPI block regions for field control and leakage reduction. This segmented architecture allows each region to be optimized for its specific function while working together to provide enhanced overall performance. The segmentation also simplifies the fabrication process by allowing independent formation of each region type.
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 EPI block regions reduce the size of ESD diodes by 35% and improve the voltage rating from 1.8V to 5V, effectively protecting FinFETs from ESD-induced damage by providing a more efficient and robust ESD protection mechanism.
Implementation Method 1
The use of EPI block regions in n-type and p-type ESD protection diodes, formed through an epitaxial growth process
Data Source
AI summary
A structure comprises an N+ region formed over a first fin of a substrate, a P+ region formed over a second fin of the substrate, wherein the P+ region and the N+ region form a diode, a shallow trench isolation region formed between the P+ region and the N+ region and a first epitaxial growth block region formed over the shallow trench isolation region and between the N+ region and the P+ region, wherein a forward bias current of the diode flows through a path underneath the shallow trench isolation region.