Characterization of leakage current in thin gate oxide subjected to 10 keV X-ray irradiation

Author

Ling, C.H. ; Ang, C.H. ; Ang, D.S.

Author_Institution

Dept. of Electr. Eng., Nat. Univ. of Singapore, Singapore

Volume

47

Issue

3

fYear

2000

fDate

3/1/2000 12:00:00 AM

Firstpage

650

Lastpage

652

Abstract

Two components of the low-field current have been identified in thin oxides, following 10 KeV X-ray irradiation. The first component, observed in the direct tunneling region, can be removed by a 100°C anneal, and is also greatly suppressed if the irradiation is done in vacuum or in a nitrogen ambient, or if the oxide is preannealed before irradiation. The origin of this current is speculated to be related to adsorbed water molecules on the gate surface. The second component is observed to begin in the pre-Fowler-Nordheim tunneling (FNT) region and extends into the FNT region, only in oxides less than ~8 nm thick, and persists even after several days of anneal at 300°C. This current exhibits a power law dependence on radiation dose. The origin of this second component is believed to be due to the trap-assisted tunneling via neutral electron traps, similar to the leakage current observed in the oxide after high-voltage stress

Keywords

MOS capacitors; X-ray effects; electron traps; leakage currents; tunnelling; 10 keV; 100 degC; 300 degC; Fowler-Nordheim tunneling; MOS capacitors; Si-SiO; X-ray irradiation; adsorbed water molecules; direct tunneling region; high-voltage stress; leakage current; low-field current; neutral electron traps; power law dependence; radiation dose; thin gate oxide; trap-assisted tunneling; Annealing; CMOS technology; Electron traps; Germanium silicon alloys; Guidelines; Leakage current; MOSFET circuits; Microelectronics; Silicon germanium; Tunneling;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.824744

Filename

824744