Semiconductor Gate Electrode Segmentation for Low ON-Resistance
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Solution Overview
Problem
Semiconductor devices, such as MOSFETs and IGBTs, face challenges in minimizing ON-resistance while maintaining high breakdown voltage due to limitations in the design and structure of the gate electrode and insulating portions, which affect the current path and electric field distribution.
Innovation Solution
The semiconductor device incorporates a specific structure for the gate electrode with multiple portions and insulating layers, where the lower surface of the first portion is positioned higher than the interface between the p-type base region and n+-type source region, and the second portion opposes the n−-type drift region, p-type base region, and n+-type source region, with a gate insulating portion in between, allowing for a more efficient current flow and reduced ON-resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the gate electrode structure is simplified, then the device complexity is reduced, but the ON-resistance increases and breakdown voltage decreases
Solution Approach 1:
The gate electrode is divided into multiple portions (first gate electrode portion and second gate electrode portion) with different positions and functions. The first portion is positioned higher and overlaps with the source region, while the second portion is positioned lower and opposes the drift region, allowing each segment to contribute differently to electric field control and current flow management, thereby reducing ON-resistance without excessive complexity increase.
Solution Approach 2:
Different regions of the gate electrode structure are designed with different properties: the first gate electrode portion has a higher position to control the source region interface, while the second gate electrode portion is positioned lower to manage the drift region interface. This local differentiation optimizes electric field distribution in different areas, achieving both low ON-resistance and high breakdown voltage.
2Manufacturing precision
If the gate electrode portions are positioned lower, then the manufacturing precision is improved, but the ON-resistance increases
Solution Approach 1:
By segmenting the gate electrode into two portions at different heights, the design allows the first portion to be positioned higher for optimal electric field control (even if manufacturing precision is limited), while the second portion provides additional control at a lower position. This segmentation compensates for positioning limitations and achieves low ON-resistance.
Solution Approach 2:
The gate electrode structure utilizes the vertical dimension by positioning portions at different heights rather than relying solely on horizontal positioning precision. This three-dimensional arrangement allows effective electric field control without requiring extremely high manufacturing precision in the horizontal plane.
3Reliability
If insulating portions are extended lower, then the breakdown voltage increases, but the device complexity increases
Solution Approach 1:
The insulating portions are merged with the gate electrode structure, forming an integrated design where the insulating layers are positioned between and around the gate electrode portions and semiconductor regions. This merging reduces overall device complexity compared to having separate insulating structures while still achieving high breakdown voltage through extended insulating coverage.
Data Source
AI summary
According to one embodiment, a semiconductor device includes a first electrode, a first semiconductor region, a second semiconductor region, a third semiconductor region, a conductive portion, a gate electrode, and a second electrode. The second semiconductor region is provided on the first semiconductor region. The third semiconductor region is provided selectively on the second semiconductor region. The conductive portion is provided inside the first semiconductor region. The gate electrode is separated from the conductive portion in a first direction. The gate electrode includes a first portion and a second portion. The first portion is provided on the conductive portion. A lower surface of the first portion is positioned higher than a lower end of an interface between the second semiconductor region and the third semiconductor region. The second portion opposes the first semiconductor region, the second semiconductor region, and the third semiconductor region in a second direction.