GaN Field Plate Structure With Buffer Films for Withstand Voltage
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Solution Overview
Problem
Semiconductor devices, such as transistors and diodes, face challenges in achieving high withstand voltage and low on-resistance while preventing electric field concentration, which can lead to device deterioration and reduced reliability.
Innovation Solution
The semiconductor device incorporates a GaN-based semiconductor layer with a specific structure including field plate electrodes and insulation films to reduce electric field concentration, with buffer films strategically placed between the element region and isolation region to enhance withstand voltage and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a field plate electrode is used to prevent electric field concentration, then device reliability is improved, but device structure becomes more complex
Solution Approach 1:
The field plate electrode is formed using a multi-layer structure where a first protective film is deposited over the semiconductor layer, followed by a second protective film patterned over the first field plate electrode region. This nested arrangement of protective films over the field plate electrode reduces electric field concentration while maintaining a relatively compact device structure.
Solution Approach 2:
The patent introduces buffer films as intermediary layers between the semiconductor layer and the field plate electrode, and between adjacent field plate electrodes. These buffer films act as mediators that reduce electric field concentration at critical interfaces without requiring fundamental changes to the field plate electrode concept itself.
2Strength
If buffer films are placed between element region and isolation region to reduce electric field concentration, then withstand voltage is improved, but manufacturing process becomes more complex
Solution Approach 1:
The buffer films are formed prior to forming the field plate electrode and associated protective films. This preliminary action allows the buffer films to be integrated into the manufacturing process flow without requiring additional complex steps, as they are deposited and patterned along with the other protective and insulating layers.
Solution Approach 2:
The patent specifies that the buffer films have different dielectric constants compared to the surrounding insulation films. By changing the dielectric parameter of the buffer films, electric field distribution is optimized to reduce concentration at the element region-isolation region boundaries, thereby improving withstand voltage through material parameter selection rather than structural complexity.
Data Source
AI summary
A semiconductor device of an embodiment includes: a semiconductor layer including an element region and an element isolation region; a first insulation film provided on the semiconductor layer; a first electrode provided on the first insulation film and extending in a first direction; a second electrode provided on the semiconductor layer, arranged in a second direction intersecting with the first direction, and extending in the first direction; a third electrode provided on the semiconductor layer, arranged in the second direction, and extending in the first direction; second insulation films provided between the first insulation film and the semiconductor layer, and interposing the third electrode in the second direction; a first field plate electrode provided on the first electrode and connected to the first electrode; a second field plate electrode provided on the first field plate electrode and connected to the second electrode; and a third field plate electrode provided on the third electrode and connected to the third electrode. The second insulation films extend from the element isolation region to a part of the element region.