Power MOSFET Carrier Conduction Layout for Avalanche Tolerance
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Solution Overview
Problem
Existing power MOSFETs face challenges in achieving adequate avalanche tolerance without increasing the on-resistance, primarily due to the need to discharge minority carriers from the base region while maintaining the source region area.
Innovation Solution
The semiconductor device incorporates a carrier conduction part extending in the X-axis direction within the base region, electrically connected to the source electrode via a connection part that does not penetrate the source region, allowing for efficient discharge of minority carriers without reducing the source region area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact is formed to penetrate the source region from the source electrode to discharge minority carriers, then avalanche tolerance is improved, but the source region area decreases and on-resistance increases
Solution Approach 1:
The patent divides the base region into multiple sections by introducing insulating regions that extend from the first main surface to the second main surface. These insulating regions segment the base region into multiple independent carrier conduction paths, allowing minority carriers to be discharged through multiple parallel paths without requiring penetration of the source region, thus maintaining source region area while improving avalanche tolerance.
Solution Approach 2:
The patent introduces insulating regions extending in the thickness direction (from first main surface to second main surface) to create vertical carrier conduction paths. This dimensional approach allows minority carriers to be discharged through the thickness direction via the insulating regions and carrier conduction parts, avoiding the need to reduce source region area in the planar direction.
2Reliability
If a contact is formed to penetrate the source region to discharge minority carriers, then avalanche tolerance is improved, but on-resistance increases
Solution Approach 1:
The base region is segmented into multiple carrier conduction paths by insulating regions, creating multiple parallel discharge paths for minority carriers. This segmentation allows efficient carrier discharge without requiring a single penetrating contact that would reduce source region area and increase on-resistance.
Solution Approach 2:
The patent introduces insulating regions with carrier conduction parts as intermediary structures to discharge minority carriers. These insulating regions act as mediators that enable carrier discharge through the base region without requiring direct penetration of the source region, thus avoiding the increase in on-resistance that would result from reducing source region area.
3Reliability
If the carrier conduction part is positioned within the source region, then minority carrier discharge is achieved, but positional deviations occur and resistance increases
Solution Approach 1:
The insulating regions extend through the entire thickness of the base region, creating well-defined vertical boundaries that precisely locate the carrier conduction parts. This segmentation approach provides clear positional references that prevent deviations and ensure accurate formation of carrier discharge paths without encroaching on the source region.
Solution Approach 2:
The insulating regions serve as intermediary structures that precisely define the position of carrier conduction parts. By using these insulating regions as positional references and barriers, the patent ensures accurate positioning of carrier discharge paths while preventing them from deviating into the source region, thus avoiding resistance increases.
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 enhances avalanche tolerance while preventing an increase in on-resistance, as the carrier conduction part is formed independently of the source region, avoiding positional deviations and resistance increases.
Implementation Method 1
a carrier conduction part provided to extend in the X-axis direction in the base region (221) and electrically connected to the source electrode (11) via a connection part (42)
Data Source
AI summary
A semiconductor device according to an embodiment includes: first and second electrodes respectively provided on first and second main surfaces of a semiconductor layer; a first semiconductor region of a first conductivity type; a plurality of insulating regions formed to extend in a second direction orthogonal to a first direction from the second electrode toward the first electrode; a plurality of third electrodes provided in the plurality of insulating regions; a second semiconductor region of a second conductivity type sandwiched between the plurality of insulating regions, formed to extend in the second direction; a third semiconductor region of the first conductivity type located between the second semiconductor region and the first electrode; and a carrier conduction part formed to extend in the second direction in the second semiconductor region and electrically connected to the first electrode via a connection part not penetrating the third semiconductor region.