LDMOS Transistor Floating Electrodes Electric Field
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LDMOS transistors face limitations in breakdown voltage due to high electric field concentration at the drain, insulation structure, and well region, which restricts their performance in high-voltage applications.
Innovation Solution
The introduction of first floating electrodes embedded in the insulation structure, which are capacitively coupled with the well region and gate, disperses the voltage difference between the drain and gate, thereby increasing the breakdown voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulation structure is designed to be disposed between the drain and the gate to endure the high electric field, then the LDMOS transistor can operate under high voltage, but the high electric field may be concentrated at the adjacent area of the drain, the insulation structure and the well region, which limits the breakdown voltage
Solution Approach 1:
The patent divides the insulation structure into multiple segments by introducing floating electrodes at different positions within the insulation layer. These segmented floating electrodes (first floating electrodes and second floating electrodes) are positioned at different depths and locations to progressively distribute and reduce the electric field concentration that would otherwise occur at single critical points between the drain and gate.
Solution Approach 2:
The floating electrodes serve as intermediary elements between the drain and gate regions. These electrodes are electrically isolated (floating) and act as mediators to gradually transition the electric potential from the high-voltage drain region to the gate region, thereby reducing the direct electric field concentration at the drain-insulation structure-well region interface.
2Strength
If the insulation structure is placed between drain and gate to withstand high electric field, then high voltage operation is enabled, but the electric field concentration at the interface limits further breakdown voltage improvement
Solution Approach 1:
The insulation structure is segmented into multiple zones with floating electrodes positioned at different locations (first floating electrodes closer to drain, second floating electrodes closer to gate). This segmentation allows the electric field to be distributed across multiple interfaces rather than concentrated at a single drain-insulation-well interface, thereby improving overall breakdown voltage while maintaining electric field withstanding capability.
Solution Approach 2:
Different regions of the insulation structure are given different properties by positioning floating electrodes with specific conductivities at different locations. The first floating electrodes provide local field control near the drain region, while second floating electrodes provide field control near the gate region, creating locally optimized electric field distribution throughout the insulation structure.
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 effectively disperses the high electric field, allowing the LDMOS transistor to tolerate higher voltages and enhance its breakdown voltage performance.
Implementation Method 1
the floating electrodes are capacitively coupled with the well region and gate, disperses the voltage difference between the drain and gate
Data Source
AI summary
The present invention provides a laterally diffused metal-oxide-semiconductor (LDMOS) transistor and a manufacturing method thereof. The LDMOS transistor includes a semiconductor substrate, an insulation structure, agate structure, and a plurality of floating electrodes. The insulation structure is disposed in the semiconductor substrate. The gate structure is disposed on the semiconductor substrate. The floating electrodes are embedded in the insulation structure, wherein the floating electrode closest to the gate structure protrudes from a top surface of the insulation structure or the gate structure includes at least one branch portion embedded in the insulation structure, and the floating electrodes are separated from the gate structure.