Nitride Semiconductor Guard Ring Shielding Static Discharge
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Solution Overview
Problem
Nitride semiconductor devices face challenges in absorbing static electricity due to reduced parasitic capacitance, leading to decreased resistance against static electricity, which affects high-speed operation and reliability, especially in hetero-structures like GaN-based or InAlN-based transistors.
Innovation Solution
Incorporating a shielding layer and a two-dimensional electron gas (2DEG) in the guard ring formation region, which are in ohmic contact and electrically connected, to shield static electricity and maintain equipotentiality, thereby protecting the device region from static discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If parasitic capacitance is reduced to enable device downsizing and high-speed operation, then device speed and size are improved, but static electricity absorption capability deteriorates
Solution Approach 1:
The device is segmented into a functional region (for high-speed operation) and a guard ring formation region (for static electricity protection). The guard ring region is further divided into multiple regions with different doping concentrations, creating distinct zones that perform different functions: absorbing static electricity while maintaining low parasitic capacitance in the functional region.
Solution Approach 2:
Different regions of the device are assigned different local properties: the functional region maintains low parasitic capacitance for high-speed operation, while the guard ring formation region has high doping concentration to provide static electricity absorption capability. This local differentiation allows both requirements to be satisfied simultaneously.
2Volume of moving object
If device is downsized to reduce parasitic capacitance, then device size and speed are improved, but static electricity protection capability deteriorates
Solution Approach 1:
The solution extends the device structure into a new dimensional space by adding a guard ring formation region surrounding the functional region. This annular region provides static electricity protection without increasing the footprint of the functional device area, effectively adding protection in a radial dimension while maintaining compact size.
Solution Approach 2:
The guard ring formation region acts as an intermediary structure between the functional region and the external environment. It absorbs static electricity before it can reach the functional region, serving as a protective mediator that shields the downsized device from static electricity damage.
3Productivity
If hetero-structure is used to achieve high electron mobility and low resistance, then device speed is improved, but static electricity absorption capability deteriorates
Solution Approach 1:
The hetero-structure device is segmented into a functional region utilizing the high electron mobility characteristics for fast operation, and a guard ring formation region with high doping concentration dedicated to static electricity absorption. This segmentation allows the hetero-structure to deliver high-speed performance while the guard ring provides reliability against static electricity.
Solution Approach 2:
The hetero-structure is configured with local quality variations: the functional region exploits the high electron mobility and low resistance properties for fast operation, while the guard ring formation region has high doping concentration to provide static electricity absorption capability, creating localized protection without compromising overall device speed.
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 shields static electricity, enhances the device's resistance against static discharge, and allows for high-speed operation without increasing parasitic capacitance, thus improving the reliability of nitride semiconductor devices.
Implementation Method 1
a two-dimensional electron gas is formed in a hetero-junction portion. The two-dimensional electron gas has high electron mobility and a high electron density
Implementation Method 2
a shielding layer provided on the second nitride semiconductor layer in the guard ring formation region and electrically protecting the device region. The shielding layer is in ohmic contact with the two-dimensional electron gas
Implementation Method 3
the shielding layer and the two-dimensional electron gas are used as a guard ring which surrounds the device region
Data Source
AI summary
According to one embodiment, a nitride semiconductor device including a device region and a guard ring formation region surrounding the device region, the nitride semiconductor device includes a first nitride semiconductor layer provided in the device region and the guard ring formation region; a second nitride semiconductor layer provided on the first nitride semiconductor layer and forming a hetero-junction with the first nitride semiconductor layer; and a shielding layer provided on the second nitride semiconductor layer in the guard ring formation region and electrically protecting the device region. A two-dimensional electron gas is present near an interface between the first nitride semiconductor layer and the second nitride semiconductor layer within the first nitride semiconductor layer below the shielding layer, and the shielding layer is in ohmic contact with the two-dimensional electron gas.