GaN HEMT Gate Bridge Structure for Normally-Off Operation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Silicon-based power devices face limitations in efficiency due to properties and manufacturing processes, and high electron mobility transistors (HEMTs) with III-V compound semiconductors struggle with achieving normally-off characteristics and reduced threshold voltage dispersion.
Innovation Solution
The design of HEMTs includes a channel supply layer generating a two-dimensional electron gas, depletion forming units, and a gate electrode configuration with bridges and contact portions to form a depletion region, allowing for normally-off operation and reduced threshold voltage dispersion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a HEMT uses a heterojunction structure of compound semiconductor to achieve high electron mobility and high breakdown voltage, then electron mobility and breakdown voltage are improved, but it is difficult to achieve normally-off characteristics and threshold voltage control is poor
Solution Approach 1:
The gate structure is segmented into multiple components: gate electrode, bridge, and contact portion. The bridge connects the gate electrode to the channel supply layer while the contact portion extends under the source electrode, creating distinct functional zones that enable independent control of depletion regions and threshold voltage
Solution Approach 2:
Different regions of the gate structure have different functions: the gate electrode controls the channel, the bridge provides electrical connection, and the contact portion under the source electrode creates a localized depletion region. This local differentiation allows the HEMT to achieve normally-off characteristics while maintaining high electron mobility in the channel region
2Ease of manufacture
If silicon-based power devices are used for power control, then manufacturing is easier, but efficiency cannot be increased due to silicon property limitations
Solution Approach 1:
The HEMT uses a composite structure combining GaN layer (channel layer) and AlGaN layer (channel supply layer) to form a heterojunction. This composite material structure exploits the superior electron mobility and breakdown voltage properties of III-V compound semiconductors, achieving high efficiency power control that overcomes silicon's inherent limitations
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 enhances the HEMTs' electron mobility and breakdown voltage, achieving stable high-frequency and high-power performance with improved threshold voltage control.
Implementation Method 1
The channel supply layer configured to generate a two-dimensional electron gas (2DEG) in the channel layer
Implementation Method 2
the depletion forming unit configured to form a depletion region in the 2DEG
Data Source
AI summary
Provided are a high electron mobility transistor (HEMT) and a method of manufacturing the HEMT. The HEMT includes: a channel layer comprising a first semiconductor material; a channel supply layer comprising a second semiconductor material and generating two-dimensional electron gas (2DEG) in the channel layer; a source electrode and a drain electrode separated from each other in the channel supply layer; at least one depletion forming unit that is formed on the channel supply layer and forms a depletion region in the 2DEG; at least one gate electrode that is formed on the at least one depletion forming unit; at least one bridge that connects the at least one depletion forming unit and the source electrode; and a contact portion that extends from the at least one bridge under the source electrode.