Development of GaN and AlGaN growth platform for achieving 3.3-20kV power devices
Abstract
Vertical GaN devices are ideal for high power applications owing to their wide bandgap-originated material properties, similar to SiC. Due to higher carrier mobility made possible by superior growth techniques, and higher avalanche field, the figure of merit offered by GaN power devices is higher compared to SiC counterparts. However, the high voltage (>1.2KV) space is yet to be fully explored in GaN. Systematic research is necessary to understand the potential of GaN, which starts with a robust growth program to develop GaN epi to attain high voltage (> 5kV) p-n diodes, thereby making it a competitive technology. The high electric field strength of GaN, which only increases as we go towards Aluminum-rich Nitrides is a remarkable advantage of this material system, which will be leveraged under this program. The data relating to avalanche breakdown in GaN is still very limited and missing for Al-rich GaN since it is still not a usual form of breakdown in GaN. Problems exist with material defects, which result in premature breakdown of junction devices. In addition, device edge termination is still an issue and in many cases avalanche breakdown is dominated by device periphery. Furthermore, very little conclusive information on high field material properties can be obtained unless all three, i.e. material quality, device-design. and processing are optimized enough to ensure well-behaved uniform avalanche multiplication and breakdown.In this proposal, we will develop and deliver highest possible device-quality GaN and AlGaN epi grown homoepitaxially on single crystalline GaN substrates to fabricate high voltages p-n diodes. We have carefully chosen the metrics to evaluate the material quality of GaN grown in our MOCVD reactor, which include (low) carbon concentration, controllable impurities (less than 1E16/ cm 3) and thick, low defect density layers grown at the highest possible growth rate. Our yearly goals are set with practical and measurable milestones. Furthermore, it builds upon a legacy of work, which has helped us to understand the challenges of vertical GaN devices and possible solutions.[Approved for Public Release]
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 06, 2021
- Source ID
- N000142112167
Entities
People
- Srabanti Chowdhury
Organizations
- Office of Naval Research
- Stanford University
- United States Navy