Semiconductor Device with Segmented Regions for Fast Recovery
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Solution Overview
Problem
Existing semiconductor devices, such as free wheeling diodes used in power conversion devices like inverters, face challenges in reducing reverse recovery time, improving safe operation regions, and minimizing current and voltage vibrations during recovery, which affect the overall efficiency and reliability of the devices.
Innovation Solution
The semiconductor device incorporates a specific structure with n-type and p-type semiconductor regions, connection regions, and insulating films arranged in a particular configuration to prioritize the operation of Schottky barrier diodes at low current states and pin diodes at high current states, controlling impurity concentrations and connection region widths to minimize hole injection and enhance recovery times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a conventional diode structure is used, then the device is simple to manufacture, but the recovery time is long and current/voltage vibrations occur during recovery
Solution Approach 1:
The diode structure is segmented into multiple functional regions: an n-type semiconductor region, a p-type semiconductor region, and a Schottky barrier region with metal electrodes. This segmentation allows different regions to perform specialized functions during recovery, reducing overall recovery time while maintaining manufacturability through standard semiconductor fabrication processes.
Solution Approach 2:
Different regions of the semiconductor device are assigned different impurity concentrations and material properties. The n-type region has a first impurity concentration, the p-type region has a second impurity concentration, and the Schottky barrier region has specific metal layer compositions. This local quality differentiation enables optimized recovery characteristics in each region without complicating the overall device structure.
2Reliability
If the diode operates in reverse parallel to IGBT, then it provides free wheeling function, but it causes current and voltage vibrations during recovery that affect safe operation region
Solution Approach 1:
The invention converts the potentially harmful reverse recovery current into a beneficial process by designing a dedicated recovery path through the Schottky barrier region. The metal-n semiconductor junction provides a controlled recovery mechanism that dissipates reverse recovery energy efficiently, transforming what would be harmful vibrations into a controlled recovery process that enhances safe operation region.
Solution Approach 2:
The Schottky barrier region acts as an intermediary between the n-type and p-type semiconductor regions during recovery. The metal electrode-n semiconductor junction provides a intermediate recovery path that controls and dampens current and voltage vibrations, preventing direct harmful interactions between the main current paths and improving overall device reliability.
3Loss of energy
If impurity concentration is increased to reduce on-voltage, then conduction loss decreases, but breakdown voltage is reduced
Solution Approach 1:
The device employs local quality differentiation with distinct impurity concentration zones. The n-type semiconductor region maintains a first impurity concentration optimized for low on-voltage, while the p-type semiconductor region has a second impurity concentration optimized for high breakdown voltage. This spatial separation of optimization criteria allows simultaneous achievement of low conduction loss and high breakdown voltage without compromise.
Solution Approach 2:
The invention resolves the trade-off by transitioning from a single-dimensional impurity concentration optimization to a multi-dimensional approach. Different impurity concentrations are applied in different spatial dimensions (n-type region vs. p-type region), and different operational modes (conduction vs. breakdown) are optimized independently in their respective regions, eliminating the need to compromise between conflicting requirements.
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 on-voltage, shortens recovery time, and improves breakdown voltage, ensuring efficient and safe operation by prioritizing SBD operation at low currents and pin diode operation at high currents, thereby enhancing the overall performance of the semiconductor device.
Implementation Method 1
prioritize the operation of Schottky barrier diodes at low current states
Implementation Method 2
prioritize pin diodes at high current states
Data Source
AI summary
According to one embodiment, in a semiconductor device, The first semiconductor region is provided between the first and the second electrode. The second semiconductor region is provided between the first semiconductor region and the second electrode. The first and second connection region are electrically connected to the second electrode, reaches the first semiconductor region. The first insulating film is provided between the first connection region and the second semiconductor region and between the first connection region and the first semiconductor region. The second insulating film is provided between the second connection region and the second semiconductor region and between the second connection region and the first semiconductor region. The third connection region is provided between the first connection region and the second connection region, the third connection region is electrically connected to the second electrode, reaches the first semiconductor region or reaches the second semiconductor region.