ESD Protection Diode with Segmented Breakdown Voltage
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Solution Overview
Problem
Solid-state switches in semiconductor applications face challenges in protecting against electrostatic discharge (ESD) events, which can damage gate dielectrics, and existing ESD protection structures consume significant area while compromising thermal efficiency.
Innovation Solution
A semiconductor device with an electrostatic discharge protection structure featuring a diode structure on a polysilicon layer, where regions of opposite conductivity types are alternately arranged along a lateral direction, providing a lower breakdown voltage in the ESD protection part and a higher breakdown voltage in the edge termination part, optimizing area efficiency and thermal characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ESD protection structures are used, then gate dielectric protection is achieved, but area consumption increases significantly
Solution Approach 1:
The ESD protection structure is divided into two distinct functional segments: an ESD protection part with lower breakdown voltage for discharge protection, and an edge termination part with higher breakdown voltage for voltage blocking. This segmentation allows each part to be optimized for its specific function, reducing the total area required compared to a uniform structure.
Solution Approach 2:
Different regions of the diode structure are assigned different conductivity types and breakdown voltages according to their specific functional requirements. The ESD protection part uses doping concentrations optimized for low breakdown voltage, while the edge termination part uses doping concentrations optimized for high breakdown voltage, achieving local optimization of electrical properties.
2Reliability
If ESD protection structures are enlarged to improve protection, then ESD robustness increases, but thermal efficiency deteriorates
Solution Approach 1:
The structure is segmented into ESD protection and edge termination parts, allowing the ESD protection part to be optimized for discharge handling while the edge termination part provides thermal management. This segmentation enables independent optimization of thermal characteristics without compromising ESD protection.
Solution Approach 2:
Different regions have different thermal properties optimized for their functions. The edge termination part with higher breakdown voltage also provides better thermal characteristics, while the ESD protection part is optimized for energy dissipation, achieving local thermal optimization.
3Ease of manufacture
If uniform breakdown voltage is used throughout the diode structure, then manufacturing is simplified, but area efficiency and thermal characteristics are compromised
Solution Approach 1:
The diode structure is segmented into regions with different doping concentrations and breakdown voltages. This is achieved through selective ion implantation or diffusion processes applied to different areas, allowing manufacturing complexity to be managed through standardized semiconductor processing techniques while achieving superior area efficiency.
Solution Approach 2:
Different regions of the polysilicon layer are doped with different concentrations of dopants to create local variations in electrical properties. This local quality differentiation enables optimized area efficiency and thermal characteristics while using standard semiconductor manufacturing processes.
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 enhances ESD protection and thermal robustness while minimizing area consumption, effectively dissipating energy from ESD events and maintaining robustness against human body model tests.
Implementation Method 1
a damage of a gate dielectric between gate and source of the transistors may be caused by an electrostatic discharge event between a gate contact area and a source contact area of the semiconductor device
Implementation Method 2
A first breakdown voltage associated with the diode structure in the electrostatic discharge protection part is smaller than a second breakdown voltage associated with the diode structure in the edge termination part
Data Source
AI summary
A semiconductor device includes a semiconductor body having first and second opposing surfaces, a first isolation layer on the first surface of the semiconductor body, and an electrostatic discharge protection structure. The electrostatic discharge protection structure includes a diode structure on the first isolation layer, a first terminal and a second terminal. The diode structure includes a polysilicon layer having first regions and at least one second region of opposite conductivity type alternatingly arranged along a first lateral direction between the first terminal and the second terminal. The diode structure extends from an electrostatic discharge protection part into an edge termination part along a second lateral direction. A first breakdown voltage associated with the diode structure in the electrostatic discharge protection part is smaller than a second breakdown voltage associated with the diode structure in the edge termination part.