Degradation mechanisms of AlGaN/GaN HEMTs under 800 MeV Bi ions irradiation

• Autores: Z.F. Lei, H.X. Guo, M.H. Tang, C. Zeng, Z.G. Zhang, H. Chen, Y.F. En, Y. Huang, Y. Q. Chen, C. Peng
• Localización: Microelectronics reliability, ISSN 0026-2714, Nº. 80, 2018, págs. 312-316
• Idioma: inglés
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• Resumen

  • Abstract Degradation characteristics and mechanisms of AlGaN/GaN high electron mobility transistors (HEMTs) were investigated under swift heavy-ion irradiation. AlGaN/GaN HEMTs were exposed to 800 MeV Bi ions with fluence up to 5.28 × 1010 ions/cm2. Post-irradiation measurement shows that the saturation drain current reduced by 15%, the maximum transconductance decreased by more than 27%, and both the positive and negative gate characteristics degraded dramatically. By the off-state examination using the Photo Emission Microscopy (PEM), electroluminescence hot spots were found in the gate areas, which indicates new leakage passages produced by heavy-ion bombardment. Micro cross sections were prepared at hot spot areas by dual-beam focused ion beam (FIB) and examined using transmission electron microscope (TEM). The presence of latent tracks throughout the whole hetero-junction area was confirmed. Latent tracks, which related to the high density ionizing energy-loss, play a role of new leakage paths and account for the increment of gate leakage. Moreover, nonionizing energy-loss induced defects decrease the charge density in the two-dimensional electron gas (2DEG) and reduce the carrier mobility, leading to the degradation of device output performances.