Title :
Density of States of a-InGaZnO From Temperature-Dependent Field-Effect Studies
Author :
Chen, Charlene ; Abe, Katsumi ; Kumomi, Hideya ; Kanicki, Jerzy
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Univ. of Michigan, Ann Arbor, MI
fDate :
6/1/2009 12:00:00 AM
Abstract :
Temperature-dependent field-effect measurements were performed on radio-frequency sputtered amorphous In-Ga-Zn-O thin film transistors (TFTs). We studied the effect of temperature on the TFT electrical properties. We observed that the field-effect mobility (mu) increases and the threshold voltage (V T) shifts negatively with temperature, while the current on-off ratio and subthreshold slope (S) remain almost unchanged. We also observed that the TFT drain current (ID) is thermally activated, and the relation between the prefactor (ID0) and activation energy (E a) obeys the Meyer-Neldel rule. The density of localized gap states (DOS) was then calculated by using a self-consistent method based on the experimentally obtained E a. The result shows good agreement with the DOS distribution calculated from SPICE simulations.
Keywords :
carrier mobility; electronic density of states; gallium compounds; indium compounds; localised states; semiconductor device models; sputter deposition; thin film transistors; InGaZnO; Meyer-Neldel rule; SPICE simulations; activation energy; density of localized gap states; electrical properties; field-effect mobility; radio-frequency sputtered amorphous thin film transistors; self-consistent method; temperature-dependent field-effect measurements; threshold voltage; Amorphous materials; Electrodes; Electron beams; Gold; Performance evaluation; Radio frequency; Sputtering; Temperature distribution; Temperature measurement; Thin film transistors; Activation energy; Meyer–Neldel (MN) rule; amorphous In–Ga–Zn–O (a-InGaZnO); density of localized gap states (DOS); thin film transistor (TFT);
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2009.2019157
