Dielectric-Segmented Diode Junctions for Lower Reverse Recovery Charge
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Solution Overview
Problem
Current approaches to reduce reverse recovery charge (Qrr) in semiconductor devices often require significant trade-offs with other DC or AC parameters, leading to increased design and process complexity, and higher costs, while also failing to achieve timely reverse recovery of P-N junctions, which can cause system failures.
Innovation Solution
The implementation of a semiconductor device with a partially dielectric-filled diode junction, where dielectric regions are used to replace portions of the P-N junction, reducing the diode junction area and thereby reducing Qrr without altering the basic device structure or doping profiles, allowing for precise control of Qrr reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the diode junction area is reduced to decrease Qrr, then reverse recovery charge is reduced, but the breakdown voltage and current handling capability may be compromised
Solution Approach 1:
The diode junction is segmented by introducing dielectric regions that divide the continuous P-N junction into multiple smaller segments. This segmentation reduces the total effective junction area and Qrr while maintaining the overall device structure and breakdown voltage characteristics through the distributed arrangement of segments
Solution Approach 2:
Dielectric regions are introduced as intermediary elements between the P-type body region and N-type drift region. These dielectric intermediaries replace portions of the P-N junction, reducing Qrr while the remaining junction segments maintain the necessary breakdown voltage through proper spacing and configuration of the dielectric elements
2Loss of energy
If conventional methods are used to reduce Qrr, then reverse recovery charge decreases, but design and process complexity increases
Solution Approach 1:
The invention changes the physical parameter of the junction area by introducing dielectric regions, achieving Qrr reduction through a straightforward structural modification rather than complex doping profile adjustments or multiple processing steps. This parameter change approach simplifies the design and manufacturing process compared to conventional methods
3Loss of energy
If the P-N junction is modified to reduce Qrr, then reverse recovery charge decreases, but other performance parameters such as switching time and conduction losses may be affected
Solution Approach 1:
The dielectric regions are strategically positioned to affect only local portions of the P-N junction, creating local quality changes that reduce Qrr in specific areas while leaving other regions intact to maintain proper switching characteristics and conduction performance. This localized modification preserves overall device functionality
Data Source
AI summary
In a general aspect, a semiconductor device can include a semiconductor region of a first conductivity type and a well region of a second conductivity type. The well region can be disposed in the semiconductor region. An interface between the well region and the semiconductor region can define a diode junction at a depth below an upper surface of the semiconductor region. The semiconductor device can further include at least one dielectric region disposed in the semiconductor region. A dielectric region of the at least one dielectric region can have an upper surface that is disposed in the well region at a depth in the semiconductor region that is above the depth of the diode junction; and a lower surface that is disposed in the semiconductor region at a depth in the semiconductor region that is the same depth as the diode junction or below the depth of the diode junction.