Semiconductor Device Gate Trench Segmentation for EMC and Turn-on Loss Trade-off
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Solution Overview
Problem
Conventional semiconductor devices face a trade-off between reducing electromagnetic compatibility (EMC) noise and turn-on loss (Eon) in power conversion circuits, where increasing gate resistance lowers EMC noise but increases Eon, and vice versa, due to the relationship between dVak/dt and Eon.
Innovation Solution
The semiconductor device incorporates a first and second gate trench portion with different resistance values and time constants for their respective RC circuits, where the second gate trench portion has a higher resistance and time constant, allowing for enhanced electron injection effect to reduce turn-on loss without significantly influencing collector current, thereby improving the trade-off between dVak/dt and Eon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If gate resistance is increased to lower EMC noise, then electromagnetic compatibility noise is reduced, but turn-on loss increases
Solution Approach 1:
The gate structure is segmented into two distinct gate trench portions: a first gate trench portion that controls collector current and a second gate trench portion that generates electron injection effect. Each portion has different resistance characteristics, allowing independent optimization of EMC noise reduction and turn-on loss without the traditional trade-off.
Solution Approach 2:
Different regions of the gate structure are assigned different electrical properties. The second gate trench portion has higher resistance to generate electron injection effect for reducing turn-on loss, while the first gate trench portion has lower resistance to control collector current. This local differentiation allows simultaneous optimization of both EMC noise and turn-on loss.
2Loss of energy
If gate resistance is decreased to reduce turn-on loss, then turn-on loss is reduced, but EMC noise increases
Solution Approach 1:
The gate is divided into two functional segments with different resistance values. The first gate trench portion with lower resistance reduces turn-on loss by enabling fast switching, while the second gate trench portion with higher resistance suppresses EMC noise through controlled electron injection, eliminating the need to choose between the two opposing requirements.
Solution Approach 2:
Different local regions of the gate structure have optimized resistance characteristics for different functions. The first gate trench portion provides low resistance for efficient current control, while the second gate trench portion provides high resistance for electron injection effect, allowing both low turn-on loss and low EMC noise to coexist.
3Loss of energy
If electron injection effect is enhanced to reduce turn-on loss, then turn-on loss is reduced, but collector current fluctuations increase
Solution Approach 1:
The gate structure is segmented into two independent control regions. The second gate trench portion enhances electron injection effect to reduce turn-on loss, while the first gate trench portion maintains stable collector current control. This segmentation allows the electron injection effect to be enhanced without causing excessive collector current fluctuations.
Solution Approach 2:
Different regions of the gate have different resistance characteristics optimized for different purposes. The second gate trench portion's higher resistance enhances electron injection for turn-on loss reduction, while the first gate trench portion's lower resistance ensures stable collector current, allowing both effects to work simultaneously without conflict.
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 turn-on loss and suppresses steep collector current fluctuations, improving the trade-off between EMC noise and Eon by accumulating holes in the second gate trench portion without affecting the collector current.
Implementation Method 1
a time constant of an RC circuit constituted by the second electrical element and the second gate trench portion may be greater than a time constant of an RC circuit constituted by the first electrical element and the first gate trench portion
Implementation Method 2
allowing for enhanced electron injection effect to reduce turn-on loss without significantly influencing collector current
Data Source
AI summary
A semiconductor device includes a semiconductor substrate having a drift region of a first conductivity type; a base region of a second conductivity type in the semiconductor substrate; an emitter region of the first conductivity type in the semiconductor substrate; a first gate trench portion that is formed in the upper surface of the semiconductor substrate and is in contact with the emitter region and the base region; a second gate trench portion formed in the upper surface of the semiconductor substrate; a first electrical element electrically connected to the first gate trench portion; and a second electrical element electrically connected to the second gate trench portion, wherein a time constant of an RC circuit constituted by the second electrical element and the second gate trench portion is greater than a time constant of an RC circuit constituted by the first electrical element and the first gate trench portion.