Apr 10, 2025
3:30pm - 4:00pm
Summit, Level 4, Room 435
Hari Nair1
Cornell University1
Over the past 10 years,
β-Ga
2O
3 with an ultra-wide bandgap of 4.8 eV has emerged as a promising material for next generation power electronics. In this talk, I will outline our work on metal-organic chemical vapor deposition (MOCVD) synthesis, processing, and characterization of
β-Ga
2O
3 epitaxial thin films and heterostructures for next generation power devices.
In the first half of the talk, I will describe our work on MOCVD synthesis of
β-(Al
xGa
1-x)
2O
3/Ga
2O
3 based modulation-doped heterostructures using triethylaluminum (TEAl) and triethylgallium (TEGa) as precursors for Al and Ga, respectively. TEAl and TEGa undergo pyrolysis at low substrate temperatures via
β-hydrogen elimination mitigating carbon contamination in the epilayers. This enabled us to synthesize
β-(Al
xGa
1-x)
2O
3/Ga
2O
3 heterostructures at low substrate temperatures, key for forming sharp interfaces, abrupt doping profiles and minimal carbon contamination. Electrical characterization of these two-dimensional electron gas (2DEG) revealed record high room temperature electron mobility of 187 cm
2/Vs, the highest to-date for MOCVD grown
β-(Al
xGa
1-x)
2O
3/Ga
2O
3 2DEGs. Moreover, at cryogenic temperatures, some of these 2DEGs display Shubnikov-de Haas oscillations.
In the second half of the talk, I will outline our work on
in situ etching of gallium oxide using
tert-butyl chloride (TBCl) in an MOCVD reactor.
In situ etching followed by regrowth opens up the possibility of forming contact layers for gallium oxide based electronic devices where the critical contact layer-to-channel interface is not exposed to atmospheric contamination. This will be key for both pushing the performance envelope of gallium oxide based radio frequency and power devices. I will discuss the etch mechanism of gallium oxide using TBCl and electrical characterization of
in situetched and regrown ohmic contacts.