Particle-Based Modeling of Large Signal RF Reliability for mmwave GaN Power Amplifiers

Project: Research project


Summary of Proposal A. Innovative Claims The particle simulation capability proposed at the core of this effort is unique and, as summarized below, has been developed over the last decade through a variety of supported efforts to improve the physical contents of the simulation. Using this asset to ascertain the internal energetics of devices under reliability test conditions offers insight for mm-wave applications that would otherwise require many years of instrumentation development. DARPA has recently invested in the future of this code through a grant to provide better detailed analysis for electro-thermal co-design that treats phonon dynamics on theoretical level as charged carriers [1] and to further enhance the HB capability for mm-wave design [2]. The proposed effort would be a completely new approach to understanding the intended and unintended consequences of test condition choices for GaN HEMT devices under large signal RF conditions and place reliability analysis on a similar footing to circuit design. An important component of the modeling and simulation effort proposed in this document will be the characterization and prediction of the phenomena of generation of lattice defects and their effects on the device performance. During the proposed research program, we will use our software to systematically analyze crucial device and material features in order to correlate the longevity of the devices with their design and process flow in a technically innovative way. Such features include thread dislocations, point defects, and the broad electro-thermal properties of the material and the specific device layout. The systematic analysis will be performed both in steady-state DC condition and in transient highly non-linear AC regime with the devices operated at highfrequency and high-power. Both time-domain and frequency-domain characterization will be performed. B. Expected Outcome The knowledge that will be produced by this grant is directly related to the systematic characterization effort described above; progress reports and task completion reports will be provided to the funding institution in order to document the generation of such knowledge. Furthermore, while committed to report on the specific topics listed below, we are definitely open to include additional topics, or modifying the existing ones, based on discussions with the technical personnel of the funding agency. In other words, we envision this research effort as a strict collaborative one, which would be dynamically adjusted based on suggestions and requests coming from the technical management of the funding agency. Such suggestions and/or requests will be promptly discussed and, when possible, translated in new or different tasks that will be realized during the performance period.
Effective start/end date3/27/145/19/19


  • DOD-USAF: Air Force Research Labs (AFRL): $500,000.00


Power amplifiers
Crystal defects
High electron mobility transistors
Point defects
Reliability analysis
Dislocations (crystals)
Thermodynamic properties
Networks (circuits)