Trench Power Transistor Gate Structure With Integrated ESD Diode Strings
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Solution Overview
Problem
Semiconductor power devices, particularly trench-type power devices, are vulnerable to damage from electrostatic discharge (ESD) events due to the breakdown of gate oxide layers, leading to high current leakage or even burning.
Innovation Solution
A trench-type semiconductor power device is designed with diode strings formed by back-to-back diodes in the trench structure, which provide electrostatic discharge protection by directing instantaneous large currents away from the gate of the power transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a trench-type power device structure is used to improve area utilization and current conducting capability, then device area utilization efficiency is improved, but the device becomes more susceptible to ESD damage due to gate oxide layer breakdown
Solution Approach 1:
The patent merges the ESD protection function with the existing trench structure by forming diode strings within the trench. The semiconductor layer in the trench serves dual purposes: as part of the power device structure and as the ESD protection element. This integration eliminates the need for separate ESD protection circuits while maintaining area efficiency.
Solution Approach 2:
The trench structure is given multiple functions: it serves as the gate structure for the power device and simultaneously houses the diode strings for ESD protection. The semiconductor layer in the trench performs both device operation and ESD clamping functions, making the structure universal and multi-functional.
2Reliability
If additional ESD protection circuits are added to protect against voltage spikes, then reliability against ESD damage is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The ESD protection function is merged into the existing trench structure rather than being added as a separate circuit. The diode strings are formed within the same trench that contains the gate structure, eliminating the need for additional protection circuits and reducing overall device complexity.
Solution Approach 2:
The trench structure itself provides ESD protection through the diode strings formed within it. The structure serves its own protection needs without requiring external or additional protection circuits, making the system self-sufficient and simpler.
3Reliability
If additional ESD protection circuits are added to protect against voltage spikes, then reliability against ESD damage is improved, but manufacturing cost increases
Solution Approach 1:
The ESD protection function is merged into the existing trench structure rather than being added as a separate circuit. The diode strings are formed within the same trench that contains the gate structure, eliminating the need for additional protection circuits and reducing overall device complexity.
Solution Approach 2:
The trench structure itself provides ESD protection through the diode strings formed within it. The structure serves its own protection needs without requiring external or additional protection circuits, making the system self-sufficient and simpler.
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 integration of diode strings within the trench structure effectively protects the power device from ESD damage, enhancing reliability and reducing manufacturing costs by eliminating the need for additional ESD protection circuits.
Implementation Method 1
Semiconductor power devices are susceptible to voltage spikes caused by electrostatic discharge (ESD) events (including the human-body model or the machine model). Large instantaneous currents and voltages caused by ESD events can cause gate oxide layers of trench power devices to be broken down
Implementation Method 2
The plurality of first doped regions and the plurality of second doped regions are staggered to form a first diode string having one or more back-to-back diodes. A first end of the first diode string is electrically connected to the gate electrode
Data Source
AI summary
A trench-type semiconductor power device includes: a substrate; an epitaxial layer; a body doped region located in the epitaxial layer; a source doped region located in the body doped region; and a trench structure comprises a first semiconductor layer extending in a second direction. The first semiconductor layer includes: a first part that abuts against the body doped region and the source doped region, and serves as a gate electrode having a first conductivity type; and a second part that extends in the second direction and away from the source doped region, and comprises a plurality of first doped regions having the first conductivity type and a plurality of second doped regions having a second conductivity type. The plurality of first doped regions and the plurality of second doped regions are staggered to form a diode string having back-to-back diodes.