Nitride Semiconductor Gate Structure for Uniform Electric Fields
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Solution Overview
Problem
Semiconductor devices with direct bandgap materials face challenges in achieving uniform electric field distribution and high breakdown voltage due to variations in capacitance and thickness of doped group III-V semiconductor layers, leading to inefficiencies and increased complexity in manufacturing.
Innovation Solution
A semiconductor device design featuring a doped group III-V semiconductor layer with portions of different thicknesses and a gate layer extending into a recess, creating varying capacitances that reshape the electric field and enhance uniformity, allowing for increased breakdown voltage and reduced device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a doped group III-V semiconductor layer with uniform thickness is used, then the manufacturing process is simple, but the electric field distribution is non-uniform and breakdown voltage is limited
Solution Approach 1:
The doped group III-V semiconductor layer is divided into multiple regions with different thicknesses (first portion and second portion), where each portion has a different thickness to create varying capacitances. This segmentation allows the electric field to be redistributed uniformly across the layer, thereby increasing breakdown voltage without requiring additional field plates.
Solution Approach 2:
Different portions of the doped group III-V semiconductor layer are given different thicknesses to create local variations in capacitance. The first portion has a first thickness and the second portion has a second thickness different from the first, allowing each region to contribute differently to the overall electric field distribution, achieving uniform field distribution through localized structural variations.
2Reliability
If multiple field plates are added to achieve uniform electric field distribution, then breakdown voltage increases, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The invention extracts and eliminates the need for additional field plates by incorporating the field-shaping function directly into the doped group III-V semiconductor layer itself. By creating portions with different thicknesses within this layer, the patent achieves uniform electric field distribution without requiring separate field plate components, thereby simplifying the overall device structure and manufacturing process.
Solution Approach 2:
The doped group III-V semiconductor layer serves multiple functions: it provides doping functionality and simultaneously acts as the field-shaping element that creates uniform electric field distribution. The different thickness portions of this single layer perform the role that would traditionally require separate field plates, reducing device complexity while maintaining reliability.
3Reliability
If the doped group III-V semiconductor layer thickness is increased to提高 breakdown voltage, then breakdown voltage improves, but device size and capacitance variations increase
Solution Approach 1:
The doped group III-V semiconductor layer employs an asymmetric thickness profile with distinct first and second portions having different thicknesses. This asymmetric design allows the layer to achieve high breakdown voltage through strategic thickness variations rather than uniform thickness increase, optimizing the balance between breakdown voltage and device dimensions.
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
The design achieves a uniform electric field distribution and increased breakdown voltage, simplifying the manufacturing process and reducing the number of field plates required, while maintaining operational efficiency across various voltage levels.
Implementation Method 1
The doped group III-V semiconductor layer includes a first portion and a second portion having different thicknesses... creating varying capacitances that reshape the electric field and enhance uniformity
Implementation Method 2
reshape the electric field and enhance uniformity, allowing for increased breakdown voltage
Data Source
AI summary
The present disclosure provides a semiconductor device and a fabrication method thereof. The semiconductor device includes a first nitride semiconductor layer, a second nitride semiconductor layer, a doped group III-V semiconductor layer and a gate layer. The first nitride semiconductor layer has a first surface. The second nitride semiconductor layer is formed on the first surface of the first nitride semiconductor layer and has a greater bandgap than that of the first nitride semiconductor layer. The doped group III-V semiconductor layer is over the second nitride semiconductor layer. The doped group III-V semiconductor layer includes a first portion and a second portion having different thicknesses. The gate layer is disposed on the first portion and the second portion of the doped group III-V semiconductor layer.