Integrated MOSFET with Schottky Diode for Power Efficiency
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Solution Overview
Problem
MOSFET devices in DC/DC power systems face high power consumption and poor reverse recovery characteristics due to the use of P-N junction diodes during switching transitions, leading to potential damage and inefficiencies in buck circuits.
Innovation Solution
Integration of a MOSFET and a Schottky diode on a monolithic semiconductor die, where the Schottky diode is placed between the MOSFET and termination areas, allowing for lower forward conduction voltage and faster reverse recovery, reducing power consumption and improving frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a P-N junction diode is used during switching transitions, then the MOSFET can operate, but power consumption increases and reverse recovery characteristics deteriorate
Solution Approach 1:
The patent combines the MOSFET and Schottky diode into a single integrated device structure on one semiconductor die. The Schottky diode is formed using the same P-type ring structure that defines the MOSFET body region, merging two separate components into one unified device that eliminates the need for external P-N junction diodes and reduces overall device complexity
Solution Approach 2:
The patent changes the diode junction type from P-N junction to Schottky junction by forming a metal-semiconductor contact instead of a P-N junction. This parameter change in the junction type reduces the forward built-in voltage from approximately 0.7V to a lower value, thereby reducing power consumption during forward conduction while improving reverse recovery characteristics
2Reliability
If a fixed dead time is adopted to prevent MOSFET damage, then MOSFET reliability improves, but switching efficiency decreases
Solution Approach 1:
The patent changes the diode characteristics by using a Schottky junction instead of a P-N junction, which provides faster reverse recovery speed. This parameter change in reverse recovery time allows the circuit to operate with reduced or eliminated dead time, thereby improving switching efficiency while maintaining MOSFET protection during switching transitions
3Use of energy by moving object
If Schottky diodes are used instead of P-N junction diodes, then power consumption decreases and reverse recovery speed increases, but device complexity increases
Solution Approach 1:
The patent merges the Schottky diode and MOSFET into a single integrated structure where the P-type ring serves dual purposes: defining the MOSFET body region and forming the Schottky junction with the metal contact. This merging approach achieves the performance benefits of Schottky diodes while avoiding the complexity of separate discrete components or additional fabrication steps
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
The integrated Schottky diode reduces power consumption and enhances reverse recovery speed, improving thermal characteristics and die size utilization, thereby minimizing damage and inefficiencies in MOSFET operations during switching transitions.
Implementation Method 1
Schottky diodes have much lower forward built-in voltage than that of the P-N junction diodes due to the metal-semiconductor contact, commonly referred to as the Schottky contact
Implementation Method 2
the forward built-in voltage of the P-N junction of the diode D0 is around 0.7V
Data Source
AI summary
The present technology discloses a semiconductor die integrating a MOSFET device and a Schottky diode. The semiconductor die comprises a MOSFET area comprising the active region of MOSFET, a Schottky diode area comprising the active region of Schottky diode, and a termination area comprising termination structures. Wherein the Schottky diode area is placed between the MOSFET area and the termination area such that the Schottky diode area surrounds the MOSFET area.