Nitride Semiconductor Device With Segmented Regions For Low On-Resistance
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Solution Overview
Problem
Semiconductor devices using nitride semiconductors face challenges in reducing on-resistance while maintaining a good normally-off characteristic and high threshold voltage.
Innovation Solution
The semiconductor device incorporates specific electrode and semiconductor region structures with varying thicknesses and aluminum gallium nitride (AlGaN) compositions, along with an insulating film, to control the formation of two-dimensional electron gas and reduce leakage current, including a protrusion in the first semiconductor region and varying thicknesses in the second and third semiconductor regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional nitride semiconductor structures are used, then the device can operate with simple structure, but the on-resistance cannot be reduced sufficiently
Solution Approach 1:
The semiconductor device is divided into multiple semiconductor regions (first, second, third, and fourth regions) with different thicknesses and compositions. Each region serves a specific function: the first region provides high breakdown voltage, the second region controls threshold voltage, the third region enables low on-resistance, and the fourth region suppresses leakage current. This segmentation allows optimization of each region's properties to achieve overall low on-resistance while maintaining normally-off characteristics.
Solution Approach 2:
Different semiconductor regions are assigned different local properties including varying thicknesses (first region thicker than second region, third region thinner than fourth region) and different AlGaN compositions (varying aluminum content x1, x2, x3, x4). These localized quality variations enable each region to perform its specific function optimally, contributing to reduced on-resistance while maintaining device reliability.
2Power
If the semiconductor structure is designed to achieve low on-resistance, then current flow in on-state improves, but leakage current in off-state increases
Solution Approach 1:
The semiconductor regions are designed with asymmetric thicknesses and compositions: the first semiconductor region has greater thickness than the second region, and the third region has lesser thickness than the fourth region. The aluminum compositions also vary asymmetrically across regions. This asymmetry creates different electric field distributions that enable low on-resistance in the on-state while the fourth region specifically suppresses leakage current in the off-state.
Solution Approach 2:
The fourth semiconductor region is specifically designed with greater thickness and higher aluminum composition to preemptively suppress leakage current before it can affect overall device performance. This preliminary anti-action against leakage current allows the device to maintain low on-resistance through the other regions without suffering from excessive off-state leakage.
3Reliability
If AlGaN composition is varied to control electron gas formation, then threshold voltage increases, but manufacturing precision requirements increase
Solution Approach 1:
The invention varies the aluminum composition parameter (x1, x2, x3, x4) across different semiconductor regions to control the formation of two-dimensional electron gas and adjust threshold voltage. By systematically changing this composition parameter from region to region, the device achieves high threshold voltage and reliable normally-off characteristics while providing clear fabrication guidelines for each region's specific composition requirements.
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 suppresses leakage current in the off-state, enhances current flow in the on-state, and achieves a low on-resistance with a high threshold voltage and good normally-off operation.
Implementation Method 1
control the formation of two-dimensional electron gas and reduce leakage current
Data Source
AI summary
According to one embodiment, a semiconductor device includes first to third electrodes, and first to third semiconductor regions. The third electrode is separated from the second electrode in a first direction. The first semiconductor region includes a first partial region separated from the first electrode, a second partial region separated from the second electrode, and a third partial region separated from the third electrode. The second semiconductor region includes a fourth partial region positioned between the first electrode and the first partial region, a fifth partial region positioned between the second electrode and the second partial region, and a sixth partial region positioned between the third electrode and the third partial region. The third semiconductor region includes a seventh partial region positioned between the second electrode and the fifth partial region and an eighth partial region positioned between the third electrode and the sixth partial region.