Integrated Schottky Diode Vertical Power MOSFET Reverse Recovery
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Solution Overview
Problem
Integrating a Schottky diode with a power MOSFET to reduce reverse recovery time while maintaining performance and cost effectiveness has been challenging, as adding a discrete Schottky diode increases chip count and system cost.
Innovation Solution
A semiconductor device is formed with a vertical power MOSFET and an integrated Schottky diode, where the source electrode contacts the extended drain of the MOSFET to form the Schottky diode, connecting it to both the Schottky diode and the source region, allowing for efficient reverse recovery without the need for a discrete Schottky diode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a discrete Schottky diode is added to the power MOSFET, then reverse recovery time is reduced, but chip count and system cost increase
Solution Approach 1:
The Schottky diode is integrated directly into the power MOSFET structure by forming a Schottky contact between the source electrode and the lightly doped drain region. This merging of the diode and transistor into a single device eliminates the need for a separate discrete Schottky diode, reducing chip count while maintaining the reverse recovery time reduction benefit
Solution Approach 2:
The integrated Schottky diode serves dual functions: it provides the reverse recovery time reduction benefit of a discrete Schottky diode while simultaneously being part of the power MOSFET structure. The Schottky contact formed between the source electrode and lightly doped drain region enables the diode to function within the MOSFET's existing structure, making the device multi-functional
2Loss of time
If a discrete Schottky diode is added to the power MOSFET, then reverse recovery time is reduced, but system cost increases
Solution Approach 1:
The Schottky diode and power MOSFET are manufactured as a single integrated device using the same fabrication process and substrate. This consolidation eliminates the need for separate procurement, packaging, and assembly of discrete components, thereby reducing system cost while achieving the reverse recovery time reduction
3Loss of time
If the source electrode contacts the extended drain to form an integrated Schottky diode, then reverse recovery time is reduced and chip count is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The Schottky contact is formed locally at the interface between the source electrode and the lightly doped drain region. By concentrating the Schottky diode formation in a specific local area rather than requiring full-electrode alignment, the manufacturing precision requirement is reduced to a manageable level while still achieving the reverse recovery time reduction
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 reduces reverse recovery time, enhances high-frequency operation, and minimizes system cost by integrating the Schottky diode within the MOSFET, thereby improving performance and reducing chip count.
Implementation Method 1
forming a source electrode to contact a lightly doped drain of the vertical power MOSFET to form the Schottky diode
Data Source
AI summary
A semiconductor device containing a vertical power MOSFET with a planar gate and an integrated Schottky diode is formed by forming a source electrode on an extended drain of the vertical power MOSFET to form the Schottky diode and forming the source electrode on a source region of the vertical power MOSFET. The Schottky diode is connected through the source electrode to the source region. A drain electrode is formed at a bottom of a substrate of the semiconductor device. The Schottky diode is connected through the extended drain of the vertical power MOSFET to the drain electrode.