Power Semiconductor Drainage Region Current Density Control
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Solution Overview
Problem
Power semiconductor devices face challenges in minimizing losses, particularly conducting and switching losses, especially in preventing excessive current density near the edge termination zone, which can lead to device failure during switch-off.
Innovation Solution
The implementation of a power semiconductor device with an active cell field surrounded by a drainage region or a recombination region, where the active cell field is configured with first and second cells that control load current, each connected to the load terminal structure and the drift region, and are spatially confined by an insulation structure, with the drainage region or recombination region reducing charge carrier lifetime to manage current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the active cell field is directly adjacent to the edge termination zone, then the device structure is simpler, but excessive current density occurs near the edge termination zone during switch-off
Solution Approach 1:
The patent divides the region between the active cell field and the edge termination zone into a separate drainage region with specific doping characteristics. This segmentation allows the drainage region to independently manage charge carrier extraction, preventing excessive current density at the edge termination zone while maintaining overall device functionality.
Solution Approach 2:
The drainage region acts as an intermediary zone between the active cell field and the edge termination zone. It mediates the transition of charge carriers by providing a controlled environment for carrier extraction, thereby preventing direct interaction that would cause excessive current density at the edge termination zone.
2Reliability
If charge carrier lifetime is reduced in the drainage region, then current density near the edge termination zone is controlled, but switching losses increase
Solution Approach 1:
The patent applies local quality by creating a drainage region with specific doping characteristics (different from both the active cell field and the edge termination zone). This localized modification allows charge carrier lifetime to be optimized in the drainage region specifically, enabling current density control without adversely affecting the entire device structure.
Solution Approach 2:
The patent changes the doping parameters in the drainage region to achieve the desired charge carrier lifetime characteristics. By adjusting the doping concentration and type in this specific region, the device achieves improved current density control during switch-off while managing switching losses through localized parameter optimization.
3Loss of energy
If the mesa structure is spatially confined with total extension less than 100 nm, then conducting losses are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent addresses the manufacturing precision challenge by defining the mesa spatial confinement in multiple dimensions. The total extension of less than 100 nm is achieved through controlled dimensions in both lateral and vertical directions, providing multiple degrees of freedom for manufacturing process optimization and tolerance distribution.
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 charge carrier concentration and current density near the edge termination zone, enhancing the device's ability to prevent failure during switch-off and minimizing losses by controlling the flow of charge carriers.
Implementation Method 1
The active cell field is surrounded by a drainage region which is arranged between the active cell field and the edge termination zone, the drainage region having the second conductivity type and being electrically connected to the first load terminal structure
Implementation Method 2
Each first mesa and each second mesa are spatially confined, in a direction perpendicular to the direction of the load current within the respective mesa, by an insulation structure and exhibit a total extension of less than 100 nm in said direction
Implementation Method 3
For setting the power semiconductor device into a conducting state, during which a load current in a forward direction may be conducted, the control electrode may be provided with a control signal having a voltage within a first range so as to induce a load current path within the channel region
Implementation Method 4
the control electrode may be provided with the control signal having a voltage within a second range different from the first range so as to cut off the load current path in the channel region. Then, the forward voltage may induce a depletion region at a junction formed by a transition between the channel region and a drift region
Data Source
AI summary
A power semiconductor device is disclosed. In one example, the device includes a semiconductor body coupled to a first load terminal structure and a second load terminal structure. An active cell field is implemented in the semiconductor body. The active cell field is surrounded by an edge termination zone. A plurality of first cells and a plurality of second cells are provided in the active cell field. Each first cell includes a first mesa, the first mesa including: a first port region and a first channel region. Each second cell includes a second mesa, the second mesa including a second port region. The active cell field is surrounded by a drainage region that is arranged between the active cell field and the edge termination zone.