Date of Award
Master of Science
Department of Engineering Physics
Yung Kee Yeo, PhD
A comprehensive study of the electrical activation of silicon implanted AlxGa1-xN was performed as a function ion dose, anneal temperature, and aluminum mole fraction, Also, GaN coimplanted with silicon and nitrogen was investigated. Room temperature Hall effect measurements were used to determine carrier concentration and mobility. All the samples had a 500 Å encapsulant of AlN, and were implanted at room temperature with 200 keV silicon ions at doses ranging from 1x1013 to 1x1015 /sq cm. The GaN was also implanted with nitrogen under the same conditions in doses of 9x1012 to 9x1014 /sq cm, respectively. The samples were annealed at temperatures ranging from 1200 to 1350 °C for 30 to 120 seconds in a flowing nitrogen environment. The aluminum mole fractions considered were 0.2 and 0.3. The electrical activation efficiency for the Al0.2Ga0.8N annealed at 1350 °C and implanted with 1x1015 /sq cm was almost 90%. While the Al0.3Ga0.7N annealed at 1350 °C and implanted with 1x1015 /sq cm exhibited only about 42% activation. The activation efficiency for all the samples increased with anneal temperature, but decreased with aluminum mole fraction. The mobilities and the carrier concentrations demonstrate an increase with the anneal temperature. Although the Al0.2Ga0.8N exhibited almost perfect activation, the mobility was generally low, only 50 /sq cm/Vxs. The coimplanted GaN showed surprisingly poor results. The highest activation efficiency was only 37% for the sample annealed at 1300 °C and implanted with a dose of 1x1015 silicon ions /sq cm. The mobilities for these samples were high, on average 100 /sq cm/Vxs. The carrier concentration and activation efficiency were found to increase with implanted dose. The mobilities, however, decreased as the anneal temperature increased.
DTIC Accession Number
Chitwood, Elizabeth A., "Electrical Activation Studies of Silicon Implanted Alx Gal-x N and Coimplanted GaN" (2003). Theses and Dissertations. 4162.