1 GeV proton damage in β-Ga2O3

Abstract

The changes of electrical properties and deep trap spectra induced in n-type β-Ga2O3 by 1 GeV protons with a fluence of 4 × 1013 cm−2 were studied. The carrier removal rates were ∼100 cm−1 at this energy. For comparison, for 20 MeV proton irradiation at comparable fluences (5–10 × 1014 cm−2), the removal rate was ∼400 cm−1 for donor concentrations of 3 × 1016 cm−3 and ∼100 cm−1 for concentrations of <1016 cm−3. These removal rates were in stark contrast with modeling results that predicted the introduction rates of vacancies to be two orders of magnitude higher for 20 MeV protons. Measurements of deep electron and hole traps densities by deep level transient spectroscopy with electrical or optical injection (DLTS or ODLTS), and capacitance–voltage profiling under monochromatic light illumination showed that the 1 GeV proton irradiation resulted in the introduction of deep donors E2*(Ec-0.75 eV) and E3 (Ec-1 eV) and deep acceptors with optical ionization threshold near 2.3 eV producing a feature near 250 K in ODLTS and 3.1 eV with related ODLTS feature near 450 K. The total concentration of all deep traps was much lower than that necessary to explain the observed decrease in net donor density upon irradiation. The donor densities showed a nonuniform distribution in proton irradiated films with the concentration greatly decreased toward the surface. Possible reasons for the observed performance are discussed.

Carrier removal rates in 1.1 MeV proton irradiated α-Ga2O3 (Sn)

“…Admittance spectra (AS) [31] at frequencies from 20 Hz to 2 MHz in the temperature range 100 K-450 K, and by deep level transient spectroscopy (DLTS) [20,31]. Details of the experimental setups can be found elsewhere [18,20,24,25,[32][33][34][35][36][37].…”

“…Proton irradiations were carried out at room temperature with energies 1.1 MeV, flux of 10 11 -10 12 cm −2 s −1 and fluences 10 13 , 10 14 , 10 15 or 10 16 cm −2 . The linear accelerator I-2 serving as a proton injector of a cyclotron with proton energy up to 10 GeV was used [32,[35][36][37]. The proton energy inside the accelerator was 24.6 MeV, the proton beam exited through a port into air, with the energy reduced to 22.5 MeV and further attenuated to the required energy using a set of calibrated metal foils (degraders) reducing the energy to 1.1 MeV.…”

(Invited) Radiation Damage in the Ultra Wide Bandgap Semiconductor Ga2O3

“…Total Dose Damage Since Ga2O3 devices and more generally all wide bandgap semiconductor devices normally use metal gates, Total Ionizing Dose (TID) effects are not as important as they are in Si technology (42,(68)(69)(70)(71)(72) , which is based on MOS-gate devices. The relations between charge (e) and electric field, E (Poisson's equation) and the transport (drift/diffusion) equations depend on carrier mobility (µe,p ) and density (n,p), i.e., 𝐽𝐽 𝑛𝑛 = 𝑒𝑒µ 𝑛𝑛 𝑛𝑛𝑛𝑛 − 𝑛𝑛𝐷𝐷 𝑛𝑛 𝛻𝛻𝑛𝑛 𝐽𝐽 𝑝𝑝 = 𝑒𝑒µ 𝑝𝑝 𝑝𝑝𝑛𝑛 − 𝑛𝑛𝐷𝐷 𝑝𝑝 𝛻𝛻𝑝𝑝…”

“…Radiation tolerance is an important factor while fabricating microelectronics and typical radiation damage suffered includes total dose effects, displacement damage, and single event effects . While significant work has been done for radiation effects in GaN (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)61) and SiC (45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60)(62)(63)(64)(65)(66)(67) , the understanding of carrier removal rates, defect levels and annealing regimes for Ga2O3 is on-going (68)(69)(70)(71)(72)(73)(74) .…”

Proton damage effects in double polymorph γ/β-Ga2O3 diodes

“…9,23,24 Of course, for open space applications, much higher energies of particles and a much higher range of particles of interest is of interest. Such studies are being carried out for different semiconductors, the radiation tolerance of b-Ga 2 O 3 devices to protons in the 100 MeV-1 GeV range, 25,26 and to irradiation with high energy heavy ions have been published [27][28][29] and also demonstrate a high radiation tolerance of b-Ga 2 O 3 devices. Thus, comparing the radiation tolerance of g/b-Ga 2 O 3 test devices to that of b-Ga 2 O 3 devices looks as a justified measure of the radiation-tolerance worthiness of the g/b-Ga 2 O 3 samples in electronic sense.…”