| Summary: | We have investigated the effect of electron effective mass (<i>m</i><sub>e</sub>*) and tail acceptor-like edge traps density (<i>N</i><sub>TA</sub>) on the electrical characteristics of amorphous-InGaZnO (a-IGZO) thin-film transistors (TFTs) through numerical simulation. To examine the credibility of our simulation, we found that by adjusting <i>m</i><sub>e</sub>* to 0.34 of the free electron mass (m<sub>o</sub>), we can preferentially derive the experimentally obtained electrical properties of conventional a-IGZO TFTs through our simulation. Our initial simulation considered the effect of <i>m</i><sub>e</sub>* on the electrical characteristics independent of <i>N</i><sub>TA</sub>. We varied the <i>m</i><sub>e</sub>* value while not changing the other variables related to traps density not dependent on it. As <i>m</i><sub>e</sub>* was incremented to 0.44 m<sub>o</sub>, the field-effect mobility (<i>µ</i><sub>fe</sub>) and the on-state current (<i>I</i><sub>on</sub>) decreased due to the higher sub-gap scattering based on electron capture behavior. However, the threshold voltage (<i>V</i><sub>th</sub>) was not significantly changed due to fixed effective acceptor-like traps (<i>N</i><sub>TA</sub>). In reality, since the magnitude of <i>N</i><sub>TA</sub> was affected by the magnitude of <i>m</i><sub>e</sub>*, we controlled <i>m</i><sub>e</sub>* together with <i>N</i><sub>TA</sub> value as a secondary simulation. As the magnitude of both <i>m</i><sub>e</sub>* and <i>N</i><sub>TA</sub> increased, <i>µ</i><sub>fe</sub> and Ion deceased showing the same phenomena as the first simulation. The magnitude of <i>V</i><sub>th</sub> was higher when compared to the first simulation due to the lower conductivity in the channel. In this regard, our simulation methods showed that controlling <i>m</i><sub>e</sub>* and <i>N</i><sub>TA</sub> simultaneously would be expected to predict and optimize the electrical characteristics of a-IGZO TFTs more precisely.
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