Trench Semiconductor Layout for Avalanche Breakdown Suppression
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Solution Overview
Problem
Avalanche breakdown in semiconductor devices for power control can lead to parasitic n-p-n transistor turn-on and secondary breakdown, causing device failure due to the lack of effective control over hole current flow.
Innovation Solution
The semiconductor device design includes a second base layer with a higher carrier concentration than the first base layer, positioned to direct hole current away from the trench contact, preventing parasitic n-p-n transistor activation and secondary breakdown by ensuring the lower end of the trench contact is further towards the drain electrode than the first base layer, thus enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If avalanche breakdown occurs in the semiconductor device, then power control function is activated, but parasitic n-p-n transistor turns on causing secondary breakdown
Solution Approach 1:
The patent applies local quality by creating a second base layer with higher carrier concentration specifically in the region where hole current flows during avalanche breakdown. This localized modification of electrical properties prevents parasitic transistor activation only in the critical area without affecting other device regions, thereby enabling power control while suppressing secondary breakdown.
Solution Approach 2:
The patent changes the carrier concentration parameter by forming a second base layer with higher carrier concentration than the first base layer. This parameter modification alters the electrical characteristics of the semiconductor structure to redirect hole current away from the trench contact, preventing parasitic n-p-n transistor turn-on while maintaining the avalanche breakdown power control function.
2Reliability
If the trench contact is positioned closer to the drain electrode, then hole current is directed away from the contact, but device structure becomes more complex
Solution Approach 1:
The patent segments the base region into two distinct layers: a first base layer and a second base layer with higher carrier concentration. This segmentation allows independent optimization of each layer's properties, enabling the second base layer to be positioned and configured specifically to direct hole current away from the trench contact while maintaining overall device functionality.
Solution Approach 2:
The patent introduces an additional dimensional aspect by adding a second base layer in the vertical stacking direction, creating a multi-layered base structure. This dimensional expansion provides an extra degree of freedom for controlling hole current distribution and preventing parasitic transistor activation without fundamentally redesigning the overall device architecture.
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 design effectively suppresses secondary breakdown, maintains high breakdown voltage, and ensures high reliability by managing hole current flow and electric field distribution, allowing for high-speed operation with reduced output capacitance and charge amount.
Implementation Method 1
When avalanche breakdown occurs in a semiconductor device for power control, there are cases where a parasitic n-p-n bipolar transistor turns on, and secondary breakdown occurs
Data Source
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AI summary
A semiconductor device includes a first electrode (11), a second electrode (14), a first semiconductor layer (21+22), a third electrode (12), a second semiconductor layer (23), a third semiconductor layer (24), a fourth electrode (13), and a fourth semiconductor layer (25). The third semiconductor layer extends from the second semiconductor layer toward the first electrode side. A lower end (24a) of the third semiconductor layer at the first electrode side is positioned further toward the first electrode side than the lower surface of the second semiconductor layer and is separated from the insulating body. The fourth electrode faces the second semiconductor layer via an other portion (32) of an insulating body (30). The fourth semiconductor layer is located between the second semiconductor layer and the second electrode and electrically connected with the second electrode.