IGBT Diode Junction Structure for Lower Reverse Recovery Loss
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Solution Overview
Problem
Current semiconductor devices with integrated IGBT and diode regions face challenges in minimizing reverse recovery loss and chip area due to inefficient hole injection control during reverse recovery, particularly in reverse conducting IGBTs.
Innovation Solution
The semiconductor device incorporates a diode portion with an Ohmic junction region and a Schottky junction region, along with a boundary region and a reach-through prevention region, to suppress hole injection and reduce reverse recovery loss, while optimizing the chip area by using specific doping concentrations and trench structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an integrated IGBT and diode region structure is used, then chip area is reduced, but reverse recovery loss increases due to inefficient hole injection control
Solution Approach 1:
The patent applies local quality by creating distinct regions within the diode portion with different doping concentrations. Specifically, a first region with higher doping concentration and a second region with lower doping concentration are formed adjacent to each other. This local variation in doping quality enables differentiated hole injection control in different areas, reducing reverse recovery loss while maintaining the integrated structure's area efficiency.
Solution Approach 2:
The patent utilizes parameter changes by varying the doping concentration parameter across different regions. The first region has a doping concentration of 1×10^16 to 1×10^18 atoms/cm³, while the second region has a doping concentration of 1×10^14 to 1×10^16 atoms/cm³. This parameter variation optimizes hole injection characteristics and reduces reverse recovery loss in the integrated IGBT-diode structure.
2Ease of manufacture
If uniform doping concentration is used in diode region, then manufacturing process is simplified, but hole injection control during reverse recovery is inefficient
Solution Approach 1:
The patent implements local quality by dividing the diode region into multiple zones with different doping concentrations. The first region (higher doping: 1×10^16 to 1×10^18 atoms/cm³) and second region (lower doping: 1×10^14 to 1×10^16 atoms/cm³) are formed adjacent to each other, enabling localized optimization of hole injection control while maintaining manufacturing feasibility through selective doping processes.
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 effectively reduces reverse recovery loss and minimizes the invalid region, leading to a smaller chip area and improved performance by controlling hole injection and carrier density during reverse recovery.
Implementation Method 1
a diode portion (80), wherein the diode portion comprises an Ohmic junction region (87) and a Schottky junction region (88)
Implementation Method 2
a diode portion (80), wherein the diode portion comprises an Ohmic junction region (87) and a Schottky junction region (88)
Data Source
AI summary
The diode portion includes: a plurality of trench portions, a drift region of a first conductivity type, an anode region of a second conductivity type provided above the drift region and having a doping concentration higher than that of a base region; and a second conductivity type region provided on the front surface of the semiconductor substrate above the anode region and having a doping concentration higher than that of the anode region, and the diode portion includes a Schottky junction region in which the anode region is provided on the front surface of the semiconductor substrate and an Ohmic junction region in which the anode region and the second conductivity type region are provided on the front surface of the semiconductor substrate.