Summary:
UCLA researchers in the Department of Mechanical and Aerospace Engineering have developed device structures and a method for fabrication of wide band gap and ultra-wide bandgap radio frequency devices with high-performance thermal management properties.
Background:
With the increasing use of wireless and cell phone technology, the electromagnetic spectrum has become increasingly congested, resulting in degraded communication performance. In order to overcome these issues, radio frequency (RF) electronics utilize wide band gap (WBG) and ultra-wide bandgap (UWBG) semiconductors which can be much more powerful than current technology. However, these devices typically are silicon and gallium nitride-based devices which suffer from issues such as thermal management issues and hot spots, which reduce their performance and reliability. Current solutions involve the use traditional materials that have high thermal conductivity (HTC) such as silicon carbide or diamond as heat spreaders in such devices, but a large thermal resistance has usually been found at interfaces within the WBG or UWBG device architecture and limits the effectiveness of such solutions. Moreover, the traditional materials can be expensive and difficult to integrate. Therefore, there is a need for new materials that can address these thermal management issues while still retaining the improved performance and power of WBG and UWBG based devices.
Innovation:
UCLA researchers have developed heterostructure device structures by integrating a new HTC semiconductor, boron arsenide (BAs) into WBG and UWBG devices, for high-performance thermal management. This innovation has been shown to have over three times the thermal conductivity higher that current industrial standard for HTC materials (i.e., copper or silicon carbide), and reduces the thermal resistance near electronics junctions by a factor of 10. For operating HEMTs devices using this innovation, experimental testings have verified substantially improved hot spot temperatures and device stability beyond the state-of-the-art technologies under the same high operation power. Experiments have shown that the UCLA technology has a clear advantage over diamond or silicon carbide as a cooling substrate. By reducing these thermal fluctuations, RF and high-powered devices have demonstrated improved performance. Furthermore, due to its compatibility with current WBG and UWBG semiconductor materials, the technology can be easily adapted with current electronic systems.
Potential Applications:
- RF electronic systems
- High powered electronic devices
- Improved replacement for thermal grease
- Thermal management for electronic, optoelectronic, and photonic devices
Advantages:
- Improved electronic performance
- High power, high frequency, and high stability
- Improved thermal management
- Reduced hot spots
- Can be used with current RF electronics.
Patent Application:
Integration of boron arsenide into power devices and semiconductors for thermal management
Status of Development:
The material and methods has been successfully generated and tested with WBG and UWBG electronic systems.
Related Papers:
Kang, J.S., Li, M., Wu, H. et al. Integration of boron arsenide cooling substrates into gallium nitride devices. Nat Electron 4, 416–423 (2021). https://doi.org/10.1038/s41928-021-00595-9
Publications:
PhysicsWorld: New semiconductor cools computer chips