Navy scientists have improved the thermal management for optoelectronic devices, such as field-effect and high electron mobility transistors. The patented technology is available via license agreement to companies that would make, use, or sell it commercially.
The parasitic capacitance between the gate and drain and between the gate and source can significantly affect the efficiency of Gallium-nitride (GaN)-based High Electron Mobility Transistors (HEMT), especially at high frequencies. A key determinant of the capacitance of the gate to the drain, source, and body is the thickness and dielectric constant of passivation materials in the gate-to-drain and gate-to-source regions. A passivation material layer with a lower dielectric constant will have lower gate-to-drain and gate-to-source capacitances.
Improvements in material growth, device design, and device fabrication have enhanced power-added efficiencies. However, GaN HEMTs designed for RF, microwave, millimeter-wave, and power switching applications are severely limited by the ability to dissipate heat and must run at significantly reduced power levels, pulse length, and duty cycle. Past methods to implement thermal management by depositing diamond on electronic devices led to an additional capacitive coupling between the gate and the drain resulting in a loss of gain at high frequencies.
Navy scientists have invented a device structure and method for improving thermal management in highly scaled, high-power electronic and optoelectronic devices such as GaN Field Effect Transistors (FET) and more specifically, AlGaN/GaN HEMT devices. Suspended diamond air bridges between the source and the gate, and between the gate and the drain, remove waste heat. This is achieved by depositing a diamond material layer on a sacrificial layer in a semiconductor heterostructure, which is later removed, leaving only the suspended diamond air bridge.
- The diamond air bridge significantly reduces capacitive coupling between the drain and the gate by suspending the diamond above the transistor, which results in low dielectric constant air between the gate and the drain
- The diamond material layer can be grown on the surface of a dielectric material layer, the III-nitride material surface, or on the surface of a diamond nanocrystalline nucleation layer, can be optimized to have a high thermal conductivity at the growth interface with the underlying material, and can be implemented at several points in any device fabrication sequence
- Businesses can commercialize the technology by licensing U.S. Patent 10,312,175 from the Navy
- License fees paid to the Navy are negotiable
- Businesses that license the technology may have the opportunity to pursue collaborative research with the inventors
- Testing data may be available to companies evaluating the technology
- TechLink guides businesses through evaluation and licensing; services provided at no cost