Device Performance and Reliability Characterization of Interface and Bulk Effect in Amorphous Indium Gallium Zinc Oxide (a-IGZO) Thin Film Transistor

We have investigated the relation of device performance and reliability characteristic on the a-IGZO TFTs fabricated by the different channel deposition conditions. Specific conditions of RF and DC sputtering are described as follows; magnetron power density of (1.4 W/cm(2))/(2.0 W/cm(2)) in Ar/O-2 gas ratio of (65/35)/(72/28), and the entire gas pressure was (5.0 mTorr) and (3.4 mTorr), respectively. In transfer characteristic curve of the each fabricated device, electrical characteristic of DC device was more superior to RF one. And the results of C-V characteristic depending on frequency showed that RF device has bad channel quality. However, threshold voltage degradation on the normalized gate bias stress and C-V hysteresis characteristic mean that DC device is worse than RF one about the interface characteristic. From these results, we can know that electrical characteristic is more affected by channel traps than interface characteristic and the device showing superior electrical characteristic doesn't guarantee good reliability invariably. And this result may be related with high magnetron power density in DC sputtered device.