(Color online) Hole trap spectra in ELOG n-GaN irradiated with different doses of 10 MeV electrons (a) dose of 1.6 × 1016 cm−3 and (b) 1.4 × 1017 cm−3.
Decrease in electron concentration (a) or electron mobility (b) in n-GaN films of different doping concentration irradiated with 10 MeV electrons to different doses. Reprinted with permission from J. Appl. Phys. 109, 123703 (2011). Copyright 2011 American Institute of Physics.
(Color online) Schematic of (a) perfect GaN lattice prior to irradiation, (b) point defects created by ionizing radiation, and (c) Gossick zones typical of neutron irradiation.
Carrier removal rates in n-GaN films or AlGaN/GaN heterostructures as a function of dose for different types of radiation.
Carrier removal rates by protons in InAlN/GaN and AlGaN/GaN HEMTs.
(Color online) Schematic of initial stage (a) and final stage (b) of growth and dislocation propagation in ELOG GaN.
(Color online) (a) Carrier removal rates for neutron irradiated MOCVD (solid triangles) and ELOG n-GaN (open triangles) samples with various donor doping; also shown are carrier removal rates for two bulk HVPE samples (solid diamonds). (b) Decrease in carrier concentration in n-GaN films grown by MOCVD or the ELOG process as a function of fast neutron dose. Reprinted with permission from J. Vac. Sci. Technol. B 28, 608 (2007). Copyright 2007 American Vacuum Society.
SEM pictures of ELOG GaN-after neutron irradiation of, inclined dislocation bands propagate into the low-dislocation density ELOG regions. There is also an increased EPD in high-dislocation density areas (increased by ∼4 × 107 cm−2 from 5 × 107 cm−2).
(Color online) Electron and hole traps in neutron irradiated ELOG regions.
(Color online) Sheet resistivity as a function of annealing temperature for undoped GaN sample irradiated with fast and thermal neutrons to a fluence of 1.5 × 1017 cm−2. The position of the Fermi level at different stages is also shown.
(Color online) Transfer characteristics from AlGaN/GaN HEMTs before and after irradiation at 10 MeV (a). The extrinsic transconductance, gm, was reduced and there was a positive shift for the threshold voltage, Vth. The reverse and forward gate I-V characteristics of the HEMTs before and after proton irradiation at 10 MeV are shown in (b). Reprinted with permission from J. Vac. Sci. Technol. B 31, 021205 (2013). Copyright 2013 American Vacuum Society.
(Color online) Off-state gate currents as a function of drain voltage for the unirradiated and 10 MeV proton irradiated HEMTs as a function of dose. Reprinted with permission from J. Vac. Sci. Technol. B 31, 022201 (2013). Copyright 2013 American Vacuum Society.
(Color online) EL spectrum from 445 nm InGaN/GaN LED before and after 40 MeV proton irradiation to doses of 5 × 109 or 5 × 1010 cm−2.
Defects introduced by various types of irradiation in GaN.
Effect of Co-60 gamma ray dose on AlGaN/GaN HEMTs. IDS is drain–source current, Gm is transconductance, and Vth is threshold voltage (after Ref. 146 ).
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