Trench Gate and Field Plate Semiconductor Component
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Solution Overview
Problem
High voltage power switching devices face a trade-off between breakdown voltage and on-state resistance, leading to increased switching losses and complex, costly manufacturing processes, particularly due to the inherent P-N diode in Power MOSFETs which causes reverse recovery time delays and losses.
Innovation Solution
A semiconductor component with a trench gate structure and a separate field plate trench, where a self-aligned unitary contact is formed to the body, source, and field plate, reducing transistor size and manufacturing complexity while enhancing breakdown voltage and reducing switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a trench gate structure with field plate in the same trench is used, then on-state resistance is reduced and switching speed is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent divides the structure into separate trenches: one trench for the gate structure and another trench for the field plate. This segmentation allows each component to be formed independently using standard processing techniques, reducing manufacturing complexity while maintaining the performance benefits of both the trench gate and field plate structures.
Solution Approach 2:
The patent introduces a dielectric material as an intermediary between the gate structure and the field plate structure. This dielectric layer simplifies the manufacturing process by allowing independent formation of each structure while maintaining proper electrical isolation and alignment, thereby reducing overall device complexity.
2Reliability
If breakdown voltage is increased, then device reliability is improved, but on-state resistance increases
Solution Approach 1:
The patent segments the voltage blocking and current conduction functions into separate structures: the trench gate structure provides high breakdown voltage through its deep depletion region, while the field plate structure reduces on-state resistance by creating a low-resistance path. This functional segmentation resolves the trade-off between breakdown voltage and on-state resistance.
Solution Approach 2:
The patent applies different structural qualities to different regions: the trench gate region is designed with specific depth and doping to optimize breakdown voltage, while the field plate region is designed with different geometry and doping to minimize on-state resistance. This local optimization allows simultaneous achievement of high breakdown voltage and low on-state resistance.
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 achieves lower on-state resistance, higher breakdown voltage, and reduced switching losses, while being cost-efficient to manufacture, by utilizing a self-aligned contact structure that simplifies the manufacturing process and improves device performance.
Implementation Method 1
When a voltage of sufficient strength is applied to the gate structure to place the MOSFET device in an on state, a conduction channel region forms between the source and drain regions thereby allowing current to flow through the device
Implementation Method 2
This inherent P-N diode turns on under certain operating conditions and stores charge across the P-N junction. When a sudden reverse bias is applied to the P-N diode, the stored charge produces a negative current flow until the charge is completely depleted
Data Source
AI summary
A semiconductor component that includes a field plate and a semiconductor device and a method of manufacturing the semiconductor component. A body region is formed in a semiconductor material that has a major surface. A gate trench is formed in the epitaxial layer and a gate structure is formed on the gate trench. A source region is formed adjacent the gate trench and extends from the major surface into the body region and a field plate trench is formed that extends from the major surface of the epitaxial layer through the source and through the body region. A field plate is formed in the field plate trench, wherein the field plate is electrically isolated from the sidewalls of the field plate trench. A source-field plate-body contact is made to the source region, the field plate and the body region. A gate contact is made to the gate region.