Insulated Floating Anode Regions in PiN Diodes
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Solution Overview
Problem
PiN diodes in switching power supplies face sub-optimal reverse recovery performance, limiting maximum switching frequency due to inefficient charge carrier removal, and existing modifications often increase leakage currents or threshold voltage.
Innovation Solution
The diode structure incorporates electrically insulated floating anode wells between contacted anode wells, allowing increased hole injection into the intrinsic region, enhancing forward current intensity and reverse recovery performance without increasing leakage currents or threshold voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If recombination centers are introduced to increase charge carrier removal speed, then reverse recovery performance is improved, but leakage currents increase
Solution Approach 1:
The anode is segmented into multiple anode regions (first anode region and second anode region) that are spatially separated and independently controlled. The first anode region is electrically connected to the anode electrode while the second anode region is electrically isolated, creating distinct functional zones that manage charge carrier removal and leakage current suppression separately
Solution Approach 2:
Different regions of the anode are given different electrical properties: the first anode region has conductive properties for charge carrier removal, while the second anode region has insulating properties to suppress leakage currents. This local differentiation allows each region to optimize its specific function without compromising the other
2Speed
If cathode structure is modified to improve reverse recovery, then charge carrier removal is enhanced, but peak reverse current intensity increases
Solution Approach 1:
The anode is divided into multiple regions with different electrical connection states, allowing gradual and distributed charge carrier removal rather than simultaneous extraction, which smooths the reverse current profile and reduces peak intensity
Solution Approach 2:
The second anode region acts as an intermediary structure that provides a controlled path for charge carrier removal while maintaining electrical isolation from the main anode electrode, thereby managing reverse recovery without generating high peak currents
3Speed
If anode structure is modified to improve reverse recovery, then charge carrier removal is enhanced, but threshold voltage increases
Solution Approach 1:
The electrical isolation of the second anode region creates localized electric field distribution that enhances charge carrier removal efficiency without requiring a uniform increase in threshold voltage across the entire device, thus maintaining low threshold voltage while improving reverse recovery
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 improves the efficiency and maximum switching frequency of PiN diodes, particularly in switching mode power supplies, by increasing hole concentration and uniformity of the electric field, while maintaining low leakage currents and threshold voltage.
Implementation Method 1
charge carriers are injected from said at least one floating anode region into the intrinsic region in response to the applying of a control voltage between the anode electrode and the cathode electrode exceeding a threshold voltage of the diode
Data Source
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AI summary
A diode (100; 200) is proposed. The diode is integrated on a chip (105) of semiconductor material having an anode surface (105a) and a cathode surface (105c) opposite to each other. The diode comprises at least one cathode region (120) having a doping of a first type, the cathode region extending from the cathode surface in the chip. Furthermore, the diode comprises an intrinsic region (130) having a doping of the first type with a dopant concentration lower than a dopant concentration of the cathode region, the intrinsic region extending between the anode surface and the cathode region. In addition, the diode comprises a plurality of anode regions (135c, 135f) having a doping of a second type, each anode region extending from the anode surface in the intrinsic region. The diode further comprises a cathode electrode (110) of electrically conductive material electrically coupled with said at least one cathode region on the cathode surface, and an anode electrode (115) of electrically conducting material. In the solution according to an embodiment of the present disclosure, one or more contacted anode regions (135c) of said anode regions are electrically coupled with the anode electrode on the anode surface, and one or more floating anode regions (135f) of said anode regions are electrically insulated from the anode electrode. The diode is configured so that charge carriers are injected from said at least one floating anode region into the intrinsic region in response to the applying of a control voltage between the anode electrode and the cathode electrode exceeding a threshold voltage of the diode.