HEMT Gate Passivation Structure for Lower Leakage Currents
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Solution Overview
Problem
Existing semiconductor devices face challenges in effectively managing gate leakage currents and surface state densities due to the direct contact between gate electrodes and group III-V dielectric layers, which affect the performance and reliability of high-electron-mobility transistors (HEMTs).
Innovation Solution
The semiconductor device incorporates a passivation layer that separates the gate electrode from the group III-V dielectric layer, using materials like silicon nitride or oxide to isolate the gate electrode and reduce direct contact, thereby minimizing gate leakage currents and surface state densities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the gate electrode is in direct contact with the group III-V dielectric layer, then the device structure is simpler, but gate leakage currents increase and surface state densities worsen
Solution Approach 1:
A passivation layer is introduced as an intermediary between the gate electrode and the group III-V dielectric layer. This passivation layer acts as a mediator that prevents direct contact, thereby reducing gate leakage currents and surface state densities while maintaining device functionality.
Solution Approach 2:
The interface between the gate electrode and the dielectric layer is segmented by introducing a separate passivation layer. This segmentation divides the original direct contact interface into two distinct interfaces, allowing each layer to perform its specific function independently and reducing harmful interactions.
2Ease of manufacture
If the gate electrode is in direct contact with the group III-V dielectric layer, then the manufacturing process is simpler, but surface state densities increase
Solution Approach 1:
The passivation layer serves as a protective intermediary that reduces surface state densities at the gate electrode interface. Although it adds a manufacturing step, the layer is formed using standard semiconductor processing techniques, making the additional complexity manageable while significantly improving device performance.
3Device complexity
If the gate electrode is in direct contact with the group III-V dielectric layer, then the device structure is simpler, but operational stability decreases
Solution Approach 1:
The passivation layer acts as a stable intermediary that protects the gate electrode from direct interaction with the dielectric layer, thereby improving operational stability. This intermediate layer prevents charge trapping and interface state formation that would otherwise degrade device performance over time.
Solution Approach 2:
The passivation layer provides beforehand cushioning by preventing harmful interactions between the gate electrode and dielectric layer before they can occur. This protective layer is in place from the beginning, cushioning against potential damage and ensuring long-term device stability.
Data Source
AI summary
Some embodiments of the disclosure provide a semiconductor device. The semiconductor device comprises: a substrate; a first nitride semiconductor layer on the substrate; a second nitride semiconductor layer on the first nitride semiconductor layer and having a band gap greater than a band gap of the first nitride semiconductor layer; a group III-V dielectric layer disposed on the second nitride semiconductor layer; a gate electrode disposed on the second nitride semiconductor layer; and a first passivation layer disposed on the group III-V dielectric layer, wherein the group III-V dielectric layer is separated from the gate electrode by the first passivation layer.