Trench Shield Electrode for ESD Protection in Semiconductor Devices
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving enhanced electrostatic discharge (ESD) protection with reduced area consumption and improved thermal characteristics, particularly in solid-state switches like MOSFETs and IGBTs, where ESD protection structures require significant area and can be inefficient in terms of topology and thermal management.
Innovation Solution
A semiconductor device structure incorporating a trench structure with a shield electrode, dielectric structure, and diode structure, where the diode is placed between the surface and the dielectric, and the shield electrode is positioned between the dielectric and the bottom of the trench, providing electrical shielding and reducing thermal impedance while minimizing surface topology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ESD protection structures are provided to protect the gate dielectric from electrostatic discharge, then the reliability of the transistor is improved, but the area consumption of the semiconductor device increases
Solution Approach 1:
The ESD protection structure is nested within the trench structure by integrating the diode structure between the gate electrode and the bottom surface of the trench, with the shield electrode positioned between the diode structure and the trench bottom. This nested configuration allows the ESD protection functionality to be embedded within the existing device architecture without requiring additional lateral space, thereby improving reliability while minimizing area consumption.
2Area of stationary object
If the ESD protection structure area is reduced to improve area efficiency, then the area consumption is reduced, but the thermoelectric safe operating area and thermal characteristics deteriorate
Solution Approach 1:
The invention transitions from a planar ESD protection structure to a vertical three-dimensional configuration within the trench. The diode structure extends vertically between the gate electrode and the shield electrode, utilizing the depth dimension of the trench rather than requiring additional lateral area. This vertical arrangement reduces area consumption while the shield electrode provides thermal management pathways, thereby maintaining improved thermal characteristics despite the reduced footprint.
3Reliability
If a shield electrode is added between the diode structure and the trench bottom to improve ESD protection, then the ESD robustness is enhanced, but the device complexity increases
Solution Approach 1:
The shield electrode serves multiple functions simultaneously: it provides electrostatic shielding to enhance ESD robustness by preventing electric field penetration to the trench bottom, acts as an electrical connection element, and contributes to thermal management. By integrating this single element to fulfill multiple roles, the structure achieves enhanced ESD protection without proportionally increasing device complexity, as the shield electrode can be formed using existing fabrication processes and materials.
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 enhances ESD protection, reduces area consumption, and improves thermal characteristics by integrating the diode within the trench structure, offering improved electrostatic discharge robustness and thermal performance without increasing the device's surface topology.
Implementation Method 1
The shield electrode is arranged between the first part of the dielectric structure and a bottom of the trench structure
Implementation Method 2
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
Data Source
AI summary
A semiconductor device includes a trench structure extending into a semiconductor body from a first surface. The trench structure has a shield electrode, a dielectric structure and a diode structure. The diode structure is arranged at least partly between the first surface and a first part of the dielectric structure. The shield electrode is arranged between the first part of the dielectric structure and a bottom of the trench structure. The shield electrode and the semiconductor body are electrically isolated by the dielectric structure. Corresponding methods of manufacture are also described.