Effects of interface traps and border traps on MOS postirradiation annealing response
- Sandia National Labs., Albuquerque, NM (United States)
Threshold-voltage and charge-pumping measurements are combined to estimate densities of radiation-induced bulk-oxide, interface, and border traps in transistors with soft 45-nm oxides. Immediately after irradiation, nearly all effects usually attributed to interface traps are actually due to border traps in these devices. During positive-bias anneal at 80 C, the interface-trap density grows by more than a factor of 10, and the border-trap density changes by less than 30%. The increase in interface-trap density is matched by a decrease in bulk-oxide-trap charge. This raises the possibility that slowly transporting or trapped protons in the oxide may be responsible for this effect. An alternate explanation is offered by H-cracking models. Latent interface-trap growth in harder 27.7-nm oxides is associated with (true) interface traps, not border traps. Switched-bias annealing of the soft 45-nm oxides reveals fast and slow border traps with different annealing responses. Trivalent Si defects associated with O vacancies in SiO{sub 2}, the E{sub {gamma}}{prime} center and the O{sub 3{minus}x}Si{sub x}Si{sm_bullet} family, are excellent candidate for slow and fast border traps, respectively. For O{sub 3{minus}x}Si{sub x}Si{sm_bullet}, x = 0 is the E{sub s}{prime} defect; x = 3 is the D center; and x = 1 or 2 have been proposed as candidates for the P{sub b1} defect on (100) Si. A hydrogen-related complex (e.g., OH{sup {minus}}) may also be a border trap. The practical significance of these results is discussed for (1) bias-temperature instabilities in thin oxides, (2) effects of burn-in on MOS radiation response, and (3) enhanced bipolar gain degradation at low dose rates.
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 203691
- Report Number(s):
- CONF-950716-; ISSN 0018-9499; TRN: 96:009650
- Journal Information:
- IEEE Transactions on Nuclear Science, Vol. 42, Issue 6Pt1; Conference: 32. annual IEEE international nuclear and space radiation effects conference, Madison, WI (United States), 17-21 Jul 1995; Other Information: PBD: Dec 1995
- Country of Publication:
- United States
- Language:
- English
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