Nitride Semiconductor Electrode Segmentation for 2DEG Contact
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving low on-resistance due to difficulties in electrically connecting electrodes to the two-dimensional electron gas (2DEG) formed in nitride semiconductor layers, particularly with insulating materials like AlN that hinder effective carrier mobility and electrode connection.
Innovation Solution
The semiconductor device design includes multiple drain and source electrodes with parts on and beneath the nitride insulating layer, strategically positioned and separated to enhance electrical connection with the 2DEG, increasing contact length and area for reduced on-resistance, featuring a laminated structure of titanium and aluminum or nickel and gold for the electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a nitride insulating layer (e.g., AlN) is used between nitride semiconductor layers, then breakdown voltage and material stability are improved, but electrical connection to 2DEG and carrier mobility deteriorate due to insulating properties
Solution Approach 1:
The drain electrode is divided into multiple segments (first drain electrode, second drain electrode, third drain electrode) positioned at different locations and depths. This segmentation allows each electrode segment to independently contact 2DEG regions, overcoming the insulating barrier by creating multiple localized connection points rather than requiring a single continuous conductive path through the insulating layer
Solution Approach 2:
The electrode structure transitions from a two-dimensional planar contact to a three-dimensional multi-level configuration. Electrodes are positioned at different heights (some on the nitride insulating layer, some beneath it) and at different lateral positions, creating vertical and horizontal diversity in contact points. This dimensional expansion allows electrical connection to 2DEG without requiring the electrode to penetrate or compromise the insulating layer's integrity
2Ease of manufacture
If electrodes are positioned only on the nitride insulating layer, then manufacturing simplicity is improved, but contact area with 2DEG and electrical connection quality deteriorate
Solution Approach 1:
The electrode configuration adds a vertical dimension to contact points by positioning some electrodes on the nitride insulating layer and others beneath it. This multi-level arrangement increases the total contact area with 2DEG without complicating the manufacturing process, as all electrodes can be formed using standard semiconductor fabrication techniques
Solution Approach 2:
The nitride insulating layer serves as an intermediary structure that enables both insulation and controlled conduction. By positioning electrodes on and beneath this layer, the design utilizes the insulating layer as a structural framework that supports and organizes multiple contact points, transforming it from a pure barrier into a functional interface for electrical connection
Data Source
AI summary
A semiconductor device includes a first nitride semiconductor layer; a second nitride semiconductor layer provided on the first nitride semiconductor layer and having a bandgap larger than a bandgap of the first nitride semiconductor layer; a nitride insulating layer provided between the first nitride semiconductor layer and the second nitride semiconductor layer; a plurality of first drain electrodes each having a part provided on the nitride insulating layer and a part provided beneath the nitride insulating layer; a plurality of second drain electrodes each having a part provided on the nitride insulating layer and a part provided beneath the nitride insulating layer; a plurality of third drain electrodes each having a part provided on the nitride insulating layer and a part provided beneath the nitride insulating layer; a plurality of fourth drain electrodes each having a part provided on the nitride insulating layer and a part provided beneath the nitride insulating layer; a plurality of first source electrodes provided between the first drain electrodes and the third drain electrodes, the first source electrodes each having a part provided on the nitride insulating layer and a part provided beneath the nitride insulating layer; and a plurality of second source electrodes provided between the first drain electrodes and the third drain electrodes, the second source electrodes each having a part provided on the nitride insulating layer and a part provided beneath the nitride insulating layer. The first drain electrodes are separated from each other by a first distance in a first direction parallel to an interface between the first nitride semiconductor layer and the nitride insulating layer. The second drain electrodes are separated from each other by a second distance in the first direction and positioned from the first drain electrodes by a third distance in the first direction and positioned from the first drain electrodes by a fourth distance in a second direction intersecting with the first direction and parallel to the interface and electrically connected to the first drain electrodes. The third drain electrodes are separated from each other by a fifth distance in the first direction and separated from the first drain electrodes and the second drain electrodes in the second direction. The fourth drain electrodes are separated from each other by a sixth distance in the first direction and positioned from the third drain electrodes by a seventh distance in the first direction and positioned from the third drain electrodes by an eighth distance in the second direction and separated from the first drain electrodes and the second drain electrodes and electrically connected to the third drain electrodes. The first source electrodes are separated from each other by a ninth distance in the first direction. The second source electrodes are separated from each other by a tenth distance in the first direction and positioned from the first source electrodes by an eleventh distance in the first direction and positioned from the first source electrodes by a twelfth distance in the second direction and electrically connected to the first source electrodes.