| AVS 59th Annual International Symposium and Exhibition | |
| Transparent Conductors and Printable Electronics Focus Topic | Thursday Sessions |
| Session TC+EM+AS+TF+EN-ThM |
| Session: | Transparent Conductors and Devices |
| Presenter: | G.S. Herman, Oregon State University |
| Authors: | G.S. Herman, Oregon State University M.S. Rajachidambaram, Oregon State University A. Pandey, Pacific Northwest National Laboratory S. Vilayurganapathy, Pacific Northwest National Laboratory P. Nachimuthu, Pacific Northwest National Laboratory S. Thevuthasan, Pacific Northwest National Laboratory |
| Correspondent: | Click to Email |
Amorphous zinc tin oxide semiconductor materials have been studied primarily as the active semiconducting material for thin film transistors (TFT) for applications including transparent and flexible electronics. Due to the amorphous nature of these materials excellent uniformity can be obtained over large areas while still having reasonably high electron mobilities (>10 cm2/Vs). Considerable control over the electrical properties of ZTO can be maintained, where insulating, semiconducting, and conductive films can be obtained by varying the processing and post-annealing conditions. We have recently characterized sputter-deposited zinc tin oxide (ZTO) as the active material for TFTs and found that the switching properties of ZTO are closely related to deposition, post-annealing, and electrical test conditions. In this presentation we will discuss bias stress induced instabilities for ZTO TFTs. We have found that devices with a backchannel exposed to the atmosphere have a positive subthreshold shift under positive bias, which can be well explained by a stretched exponential model. Using this model the shifts may be related to either electron trapping at the dielectric semiconductor interface or due to metastabilities of the active material. We have found that the adsorption of a self-assembled monolayer (SAM) on the backchannel of the TFT effectively passivates the device and significantly reduces the bias stress induced instabilities. In this study we will present contact angle measurements and x-ray photoelectron spectroscopy to better understand the interaction of the SAM with the ZTO surface, and the improved the stability of the ZTO TFTs will be discussed in regards to the interfacial chemistry of the backchannel.