Study of instabilities in amorphous-silicon thin-film transistors by transient current spectroscopy

Author

Nickel, Norbert ; Fuhs, Walther ; Mell, Helmut

Author_Institution

Fachbereich Phys., Marburg Univ., West Germany

Volume

37

Issue

1

fYear

1990

fDate

1/1/1990 12:00:00 AM

Firstpage

280

Lastpage

284

Abstract

A study of the metastable changes in a-Si:H/a-SiN:H thin-film transistors (TFTs) caused by prolonged application of high gate voltages by photoinduced discharge (PID) measurements and transient current spectroscopy (TCS) is discussed. Two effects can be distinguished: (1) a pronounced shift of the flatband voltage, which is caused by charge trapping in the dielectric, and (2) the creation of metastable states in the accumulation layer. It is found that PID is unable to detect changes of the density of defect states near the interface N_i. TCS, on the other hand, reveals that voltage stress causes an increase of N_i by up to a factor of 2. The temperature dependence of this effect indicates an activation energy for defect formation of approximately 0.7 eV

Keywords

amorphous semiconductors; electron traps; hydrogen; silicon; silicon compounds; thin film transistors; 0.7 eV; accumulation layer; amorphous Si:H-SiN:H thin film transistor; charge trapping; defect formation activation energy; defect state density; flatband voltage shift; high gate voltages; metastable changes; photoinduced discharge; temperature dependence; transient current spectroscopy; voltage stress; Current measurement; Degradation; Metastasis; Neodymium; Nickel; Partial discharges; Spectroscopy; Stress; Thin film transistors; Threshold voltage;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.43826

Filename

43826