HEMT Electrode Wiring Layout for Lower Feedback Capacitance
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Solution Overview
Problem
Nitride semiconductor HEMTs face issues with large feedback capacitance, which degrades switching characteristics.
Innovation Solution
A semiconductor device structure with a conductive film between the gate and drain wiring, electrically connected to the source electrode, reduces static capacitance and feedback capacitance by interrupting electric field lines, thereby improving switching characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional HEMT structure with electron supply layer directly below gate electrode is used, then high electron mobility is achieved, but large feedback capacitance degrades switching characteristics
Solution Approach 1:
The electron supply layer is segmented into two parts: a first electron supply layer directly below the gate electrode that is removed to reduce feedback capacitance, and a second electron supply layer at the sides that maintains high electron mobility. This segmentation allows independent optimization of switching characteristics and electron transport.
Solution Approach 2:
The first electron supply layer is extracted (removed) from directly below the gate electrode through selective etching. This extraction eliminates the source of feedback capacitance while the second electron supply layer remains to provide necessary electron supply for maintaining channel conductivity.
2Reliability
If electron supply layer is removed below gate electrode to reduce feedback capacitance, then switching characteristics improve, but electron supply for channel may be insufficient
Solution Approach 1:
Different regions of the electron supply structure are given different qualities: the first electron supply layer below the gate is removed to reduce capacitance, while the second electron supply layer at the sides is preserved to maintain electron supply. This local differentiation optimizes both switching performance and electron transport.
Solution Approach 2:
The electron supply function is transitioned from a purely vertical configuration (single layer below gate) to a three-dimensional configuration with the second electron supply layer extending laterally at the sides. This dimensional change maintains electron supply while reducing the capacitive coupling area.
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
The proposed structure effectively reduces feedback capacitance, enhancing the switching performance of nitride semiconductor HEMTs.
Implementation Method 1
at least a portion of electric lines of force between the gate electrode and the drain wiring is interrupted by the conductive film
Implementation Method 2
Due to polarization caused by lattice mismatch between GaN and AlGaN, a two-dimensional electron gas is formed
Implementation Method 3
polarization caused by lattice mismatch between GaN and AlGaN
Data Source
AI summary
A semiconductor device 1 has an electrode structure that includes source electrodes 3, a gate electrode 4, and drain electrodes 5 disposed on a semiconductor laminated structure 2 and extending in parallel to each other and in a predetermined first direction and a wiring structure that includes source wirings 9, drain wirings 10, and gate wirings 11 disposed on the electrode structure and extending in parallel to each other and in a second direction orthogonal to the first direction. The source wirings 9, the drain wirings 10, and the gate wirings 11 are electrically connected to the source electrodes 3, the drain electrodes 5, and the gate electrode 4, respectively. The semiconductor device 1 includes a conductive film 8 disposed between the gate electrode 4 and the drain wirings 10 and being electrically connected to the source electrodes 3.