Nitride Semiconductor Device Intermediate Layer Carrier Mobility
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Solution Overview
Problem
Current nitride semiconductor devices face challenges in enhancing carrier mobility in the channel region of MOSFETs, particularly in gallium nitride-based semiconductors.
Innovation Solution
Incorporating a gallium nitride-based semiconductor substrate with a gate insulating film, an intermediate layer having a smaller band gap than the gate insulating film, and a gate electrode, along with a source and drain electrode structure, where the intermediate layer forms a heterojunction with the gallium nitride layer to improve carrier mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an intermediate layer with band offset is introduced between the gallium nitride layer and gate insulating film, then carrier mobility in the channel region is improved, but device structure becomes more complex
Solution Approach 1:
An intermediate layer is introduced between the gallium nitride-based semiconductor layer and the gate insulating film. This intermediate layer has a band gap smaller than the gate insulating film and forms a band offset with the gallium nitride layer, serving as a mediator that improves carrier mobility in the channel region while maintaining proper electrical isolation.
Solution Approach 2:
The intermediate layer is selectively positioned only in the channel region where carrier mobility improvement is needed, rather than throughout the entire device. This localized approach targets the specific functional requirement while minimizing overall structural complexity.
2Reliability
If the intermediate layer avoids the source contact region, then parallel conduction is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The intermediate layer acts as a barrier that prevents parallel conduction paths between the source electrode and source region. By strategically positioning this layer to avoid the source contact region while covering the channel, it provides electrical isolation where needed without blocking necessary current flow paths.
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 significantly enhances carrier mobility in the channel region, preventing parallel conduction and 2D electron gas generation, thereby improving the overall performance of the nitride semiconductor device.
Implementation Method 1
an intermediate layer arranged between the gallium nitride-based semiconductor layer and the gate insulating film, having a band gap smaller than that of the gate insulating film, and having a band offset with the gallium nitride-based semiconductor layer
Implementation Method 2
the intermediate layer is arranged at a position opposed to the gate electrode through the gate insulating film and avoids a source contact region
Data Source
AI summary
A nitride semiconductor device includes a transistor having a channel region in a gallium nitride-based semiconductor layer. The transistor includes: a gate insulating film provided above the gallium nitride-based semiconductor layer; an intermediate layer arranged between the gallium nitride-based semiconductor layer and the gate insulating film, having a band gap smaller than that of the gate insulating film, and having a band offset with the gallium nitride-based semiconductor layer; a gate electrode provided on the gate insulating film; a first conductivity type source region provided in the gallium nitride-based semiconductor layer; and a source electrode provided on the gallium nitride-based semiconductor layer and being in contact with the source region. The intermediate layer is arranged at a position opposed to the gate electrode through the gate insulating film and avoids a source contact region in which the source electrode is in contact with the source region.