Field-Plate Semiconductor Structure for Low-Capacitance High-Voltage Switching
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Solution Overview
Problem
High-voltage transistors face challenges in achieving low on-resistance and high breakdown voltage while minimizing gate-drain capacitance and switching power loss.
Innovation Solution
The semiconductor device incorporates a substrate with source and drain regions, a gate structure, an insulating layer, and multiple field plates, where the field plate closest to the gate is electrically connected to the source region, and a body contact region is formed to reduce parasitic capacitance and enhance electric field dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high-voltage transistor structures are used, then breakdown voltage can be achieved, but gate-drain capacitance and switching power loss increase
Solution Approach 1:
The drain region is segmented into multiple doped drift regions with different doping concentrations, creating a gradient structure that divides the high-voltage stress across multiple zones. This segmentation reduces the electric field concentration at any single point, lowering gate-drain capacitance while maintaining high breakdown voltage capability.
Solution Approach 2:
Different regions of the transistor are assigned different doping concentrations and structural characteristics optimized for their specific functions. The doped drift regions have varying local properties - higher doping near the source for lower resistance, lower doping near the drain for higher breakdown voltage - resolving the contradiction between on-resistance and breakdown voltage.
2Reliability
If high breakdown voltage is achieved through conventional structures, then on-resistance increases
Solution Approach 1:
The doping concentration parameter is varied continuously across the drift region to create a gradient structure. By changing the doping parameter from high near the source to low near the drain, the invention simultaneously achieves low on-resistance (through high doping regions) and high breakdown voltage (through low doping regions), resolving the traditional trade-off.
Solution Approach 2:
The invention transitions from a uniform one-dimensional structure to a multi-dimensional gradient structure where doping concentration varies across the drift region. This dimensional complexity allows simultaneous optimization of conflicting parameters - low on-resistance through high-doping zones and high breakdown voltage through low-doping zones within the same continuous 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 reduces gate-drain capacitance and switching power loss, enabling high breakdown voltage and low on-resistance in high-voltage transistors.
Implementation Method 1
a plurality of field plates located on the insulating layer, wherein the field plate closest to the gate structure is electrically connected to the source region
Implementation Method 2
a body contact region located in the first well region, wherein the body contact region is electrically connected to the source region and the field plate closest to the gate structure
Data Source
AI summary
A semiconductor device includes: a substrate; a source region and a drain region located in the substrate; a gate structure located in the substrate between the source region and the drain region; an insulating layer located between the gate structure and the drain region; a plurality of field plates located on the insulating layer, wherein the field plate closest to the gate structure is electrically connected to the source region; a first well region located in the substrate; a body contact region located in the first well region, wherein the body contact region is electrically connected to the source region and the field plate closest to the gate structure; and a first doped drift region located in the substrate, wherein the gate structure is located between the first well region and the first doped drift region, and the drain region is located in the first doped drift region.