Integrated MOSFET Reflux Diode for Inverter Miniaturization
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Solution Overview
Problem
The integration of separate semiconductor chips for switching elements and reflux diodes in inverter circuits leads to increased module size and cost, hindering miniaturization due to adverse effects such as reverse conduction and potential destruction of switching elements.
Innovation Solution
A semiconductor device with a MOSFET structure incorporating a built-in reflux diode, featuring alternating semiconductor regions and impurity concentrations to manage impurity profiles and energy barriers, reducing conduction loss and suppressing excessive hole current, thereby integrating the diode function within the MOS structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate chips are used for switching element and reflux diode, then device reliability is improved by preventing destruction, but module size increases and miniaturization cannot be attained
Solution Approach 1:
The patent merges the switching element (MOSFET) and reflux diode into a single integrated semiconductor chip. The MOSFET and diode share common semiconductor regions and are formed in the same substrate, eliminating the need for separate chips while maintaining the protective function of the reflux diode against surge currents.
Solution Approach 2:
The semiconductor chip performs multiple functions: it acts as both a switching element (MOSFET) and a reflux diode. The integrated structure allows the same chip to provide both switching capability and reverse conduction protection, reducing the overall number of components needed in the module.
2Reliability
If separate chips are used for switching element and reflux diode, then device reliability is improved by preventing destruction, but manufacturing cost increases
Solution Approach 1:
The patent merges the switching element (MOSFET) and reflux diode into a single integrated semiconductor chip. The MOSFET and diode share common semiconductor regions and are formed in the same substrate, eliminating the need for separate chips while maintaining the protective function of the reflux diode against surge currents.
3Volume of moving object
If integrated MOS structure with alternating semiconductor regions is used, then miniaturization is achieved and cost reduced, but complex impurity concentration management is required
Solution Approach 1:
The patent employs different impurity concentrations in different semiconductor regions to optimize local performance. The first and third semiconductor regions have different impurity concentrations, allowing each region to be tailored for its specific function while maintaining overall device performance and enabling miniaturization.
4Volume of moving object
If integrated MOS structure with alternating semiconductor regions is used, then miniaturization is achieved and cost reduced, but device complexity increases
Solution Approach 1:
The patent employs different impurity concentrations in different semiconductor regions to optimize local performance. The first and third semiconductor regions have different impurity concentrations, allowing each region to be tailored for its specific function while maintaining overall device performance and enabling miniaturization.
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 approach enables miniaturization and cost reduction by integrating the reflux diode within the MOSFET, minimizing leakage current and maintaining device reliability while preventing chip destruction from surge currents.
Implementation Method 1
The third semiconductor region has an impurity concentration higher than an impurity concentration of the first semiconductor region
Implementation Method 2
A semiconductor device with a MOSFET structure incorporating a built-in reflux diode, featuring alternating semiconductor regions
Implementation Method 3
The third electrode contacts the third semiconductor region, the second semiconductor region, and the first semiconductor region via an insulating film
Data Source
AI summary
According to one embodiment, a semiconductor device includes first electrode, second electrode, and third electrodes, first, second, third, fourth, and fifth semiconductor regions. The first semiconductor region is provided between the first and second electrodes. The second semiconductor region is provided between the first semiconductor region and the second electrode. The third semiconductor region is provided between the second semiconductor region and the second electrode. The third semiconductor region has an impurity concentration higher than an impurity concentration of the first semiconductor region. The third electrode contacts the third, second, and first semiconductor regions via an insulating film. The fourth semiconductor region is provided between the first semiconductor region and the second electrode. The fifth semiconductor region is provided between the fourth semiconductor region and the second electrode. The fifth semiconductor region has an impurity concentration higher than the impurity concentration of the first semiconductor region.