Achieving Thermal Management in IMPATT and CAVETs for RF
Abstract
Approved for public release.Vertical devices based on Gallium Nitride (GaN) is predicted to deliver more power at a given operatingfrequency since GaN has a 10 times higher critical field and twice higher electron saturation velocity than Si. GaN vertical devices offer very high power density for high millimeter-wave operations. This presents a substantial advantage in power generation over Si devices, to which GaN is approximately 100 times better. GaN also has high electron saturation velocity, a property well-suited to high-frequency operation. Its intrinsic carrier concentration at 1000deg C is a mere 1015/cm3. In comparison, Si devices reach this level of intrinsic carrier concentration at 300degC and GaAs devices at 500oC. This difference allows GaN devices to operate at a much higher temperature before facing any performance degradation and breakdown.Avalanche in GaN has not been leveraged to its full potential, yet. With more high-quality native GaN substrates available recently, avalanche in GaN PN diodes is now routinely reported with proper doping profile design and appropriate edge termination techniques applied. In our previous study, different edge termination techniques, such as bevel mesa etch, sidewall ion implantation and hydrogen passivation-based field plate have been developedto achieve avalanche capability for GaN PN diodes in a voltage range of 150-2800 V. In our previous work, a structure of GaN PN diode targeted at 94GHz was proposed. By simply applying a bevel termination, recoverable breakdown at 140 V was observed for the devices. The positive temperature coefficient of breakdown voltage verified the avalanche mechanism. Some of these the exceptional properties in GaN vertical devices cannot be realized without solving the electrothermal challenges. In this proposal we will be tackling the electrothermal challenges of vertical GaN -based RF devices to deliver the maximum performance.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 03, 2023
- Source ID
- N000142312285
Entities
People
- Srabanti Chowdhury
Organizations
- Office of Naval Research
- Stanford University
- United States Navy