Accession Number : AD1029775


Title :   Characterization and Reliability of Vertical N-Type Gallium Nitride Schottky Contacts


Descriptive Note : Technical Report


Corporate Author : Naval Postgraduate School Monterey United States


Personal Author(s) : Gardner,Michael L


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1029775.pdf


Report Date : 01 Sep 2016


Pagination or Media Count : 101


Abstract : Silicon- and silicon carbide-based power devices have dominated the power electronics industry. Formany emerging high-current and high-power applications, vertical transport gallium nitride (GaN)-baseddevices are more desirable. In this study, a series of reduced-defect, vertical n-type GaN Schottky contactswere fabricated and subjected to high-current density accelerated lifetime tests to understand the physics ofcontact degradation and compare the reliability of different metallization types and process cleans. TestedSchottky metals included molybdenum, molybdenum-gold, and chromium-gold. Process cleans comparedwere a piranha etch and a hydrofluoric acid etch. Pre-stress electrical characterization confirmedfunctioning Schottky contacts and determined device electrical performance parameters. Using a stress-measure-stress system, we obtained results of high-current density accelerated lifetime testing of 170 hoursat current densities of 2.3 kAcm-2 that showed both catastrophic and non-catastrophic failures across allmetallization types and process cleans. While comparative analysis showed that molybdenum was themost reliable, identified experimental testing and non-ideal fabrication issues limited the conclusivity ofthe results. The identified constraints and initial comparative results serve to inform future Schottkycontact structural design and fabrication for future optimized testing.


Descriptors :   gallium nitrades , power electronics , semiconductors , accelerated testing , reliability , molybdenum , chromium , metalsemiconductor junctions


Subject Categories : Electrical and Electronic Equipment
      Inorganic Chemistry


Distribution Statement : APPROVED FOR PUBLIC RELEASE