Trench Transistor Dual Control Electrodes for On Resistance and Capacitance
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Solution Overview
Problem
Conventional trench transistors face challenges in achieving high breakdown voltage with low on resistance and parasitic capacitance between the gate and drain electrodes, as thicker gate insulation layers increase on resistance and more weakly doped drift zones also lead to higher parasitic capacitance, while existing solutions like additional control electrodes complicate the development process and reliability.
Innovation Solution
An integrated circuit with a trench transistor featuring two control electrodes, a gate electrode, and a field electrode in the same trench, where the field electrode is insulated and connected to a different potential, allowing for adjustable on resistance and parasitic capacitance by varying the connection scheme of field electrodes to the gate or source potential, thereby optimizing the transistor's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thicker gate insulation layer is provided to increase breakdown voltage, then breakdown voltage is improved, but on resistance increases
Solution Approach 1:
The gate insulation layer is divided into two segments: a first gate insulation layer with a first thickness and a second gate insulation layer with a second thickness greater than the first. This segmentation allows the lower portion to maintain lower on resistance while the upper portion provides higher breakdown voltage, resolving the contradiction between these two parameters.
2Strength
If a more weakly doped drift zone is provided to increase breakdown voltage, then breakdown voltage is improved, but parasitic capacitance between gate and drain increases
Solution Approach 1:
The drift zone is given non-uniform doping characteristics through the combination of different gate insulation layer thicknesses, creating local quality variations. The thinner first gate insulation layer region allows for different doping levels compared to the thicker second gate insulation layer region, enabling optimization of both breakdown voltage and parasitic capacitance in different local areas.
3Object-affected harmful factors
If an additional field electrode is provided to reduce parasitic capacitance and on resistance, then transistor performance is improved, but development process complexity increases
Solution Approach 1:
The field electrode and gate electrode are merged into a single integrated structure where the gate electrode extends into the drift zone. This combination achieves the performance benefits of separate electrodes (reduced parasitic capacitance and on resistance) while simplifying the development process by eliminating the need for additional electrode fabrication steps.
Solution Approach 2:
The gate electrode is extended into the drift zone in the vertical dimension, creating an overlapping region. This dimensional change allows the gate to exert control over the drift zone without requiring a separate field electrode, thereby reducing parasitic capacitance and on resistance while maintaining process simplicity.
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 enables a simple and effective setting of on resistance and parasitic capacitance, reducing development complexity and improving transistor efficiency by allowing for adjustable ratios of on resistance and capacitance, thus enhancing the transistor's performance and reliability.
Implementation Method 1
a field electrode (16) arranged in the trench adjacent to the gate electrode (13), the field electrode being insulated from the semiconductor body and being able to be connected to a different potential, in particular gate potential or source potential
Implementation Method 2
the gate electrode is arranged adjacent to the body zone in order to produce a conductive channel ('inversion channel') in the body zone upon application of a control potential having a suitable sign, thereby enabling a current flow in the semiconductor body
Implementation Method 3
A gate insulation layer serves for insulating the gate electrode from the semiconductor body
Data Source
AI summary
An integrated circuit including a field effect controllable trench transistor having two-control electrodes is disclosed. One embodiment provides a trench having a first control electrode and a second control electrode. A first electrical line is provided in an edge structure for electrically contact-connecting second control electrode.