Advanced electron microscopy characterization techniques, especially electron holography and nanoscale elemental mapping, will be used to identify defects and degradation mechanisms in III-nitride HEMT materials and devices. 2) Particle-based modeling of charge transport within HEMT devices will be used to predict the impact of defects on device performance and possible failure mechanisms on a microscopic scale. 2. Background Much progress has recently been made by our group in developing and refining the tools that are needed to fully understand failure mechanisms in III-nitride devices. For example, close agreement was obtained between computer simulations based on a full-band cellular Monte- Carlo approach and experimental electron holography measurements of electrostatic potential distributions across AlGaN/GaN HEMT devices. Sample preparation methods based on the focused-ion-beam (FIB) have been developed that are able routinely to provide thin, electrontransparent specimen regions of uniform thickness that extend across entire HEMT devices all the way from source to drain, and significant progress has been made towards in situ biasing experiments. Our microstructural observations have also provided more detailed knowledge of contact inclusions due to device processing, as well as contributing towards novel device concepts based on InAlN/AlN/GaN heterostructures. Overall, these results and experience make us very well placed to have a significant impact on the challenge of predicting device lifetimes.
|Effective start/end date||6/1/10 → 12/15/11|
- US Department of Defense (DOD): $380,999.00