Semiconductor Device With Trench Field Plates And Gate Electrodes
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Solution Overview
Problem
Power transistors used in automotive and industrial electronics face challenges in achieving low on-state resistance (Ron) while maintaining high voltage blocking capability, especially when switching at high frequencies and minimizing charge and conduction losses.
Innovation Solution
The semiconductor device incorporates a field effect transistor with first and second field plate structures and gate electrode structures arranged in an alternating manner, which are formed in trenches within the semiconductor substrate, allowing for improved charge compensation and reduced on-state resistance without compromising blocking characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional power transistor structures are used, then manufacturing is simpler, but on-state resistance is high and switching efficiency is poor
Solution Approach 1:
The transistor structure is divided into multiple segments including alternating field plate structures and gate electrode structures, with each serving specific functions. This segmentation allows independent optimization of each component to reduce on-state resistance while maintaining manufacturing feasibility through modular construction.
Solution Approach 2:
The patent introduces a vertical dimension by forming field plate structures and gate electrode structures in trenches extending into the semiconductor substrate. This three-dimensional arrangement enables better charge compensation and field control without significantly increasing planar footprint, thus reducing on-state resistance without proportionally increasing manufacturing complexity.
2Productivity
If switching frequency is increased, then circuit efficiency improves, but charge and conduction losses increase
Solution Approach 1:
Field plate structures are formed beforehand to establish predetermined charge compensation regions before the transistor switches. This preliminary charge distribution reduces the charge required for switching transitions, enabling higher switching frequencies with lower charge losses.
Solution Approach 2:
The patent modifies electrical parameters by introducing field plate structures that alter the electric field distribution and charge characteristics. This changes the conduction behavior to reduce conduction losses while maintaining the ability to switch at high frequencies.
3Loss of energy
If on-state resistance is reduced, then conduction losses decrease, but voltage blocking capability may be compromised
Solution Approach 1:
Different regions of the transistor are given different properties: field plate structures provide charge compensation and field control in specific areas, while gate electrode structures control conduction in other regions. This local differentiation allows simultaneous optimization of low on-state resistance in conduction regions and high voltage blocking in isolation regions.
Solution Approach 2:
Field plate structures act as intermediary elements between the gate electrode structures and the semiconductor substrate. They mediate the electric field distribution, enabling better control of both conduction and blocking characteristics, thus allowing reduced on-state resistance without compromising voltage blocking capability.
Data Source
AI summary
A semiconductor device includes a semiconductor substrate having a first surface, first and second field plate structures extending in a first direction parallel to the first surface, a plurality of gate electrode structures disposed over the first surface and extending in a second direction parallel to the first surface, the second direction being different than the first direction, and a plurality of source regions and drain regions of a first conductivity type arranged in an alternating manner at the first surface so that a drain region is disposed on one side of a gate electrode structure and a source region is disposed on the other side of the gate electrode structure. The gate electrode structures are disposed between the first and the second field plate structures. The source regions and the drain regions extend in parallel with one another along the second direction.