| AVS 65th International Symposium & Exhibition | |
| Thin Films Division | Thursday Sessions |
| Session TF-ThP |
| Session: | Thin Film Poster Session |
| Presenter: | Sung-Eun Lee, Seoul National University, Republic of Korea |
| Authors: | S.-E. Lee, Seoul National University, Republic of Korea K.-H. Lim, Seoul National University, Republic of Korea J. Park, Seoul National University, Republic of Korea J.-E. Huh, Seoul National University, Republic of Korea J. Lee, Seoul National University, Republic of Korea E.G. Lee, Seoul National University, Republic of Korea C.I. Im, Seoul National University, Republic of Korea Y.S. Kim, Seoul National University, Republic of Korea |
| Correspondent: | Click to Email |
Copper (Cu) is used in many electrode industrials because of its relatively low resistance and cost competitiveness compared to other metals. Particularly, since semiconductor and display devices require low-resistance electrodes with a high integration, interest in Cu has been more increasing. On the other hand, due to the inherent diffusion tendency, it is known that the Cu ion can easily migrate into Si or oxide based semiconductor and generate reactant with a high resistance at the interface. Thus, deterioration such as hump or abnormal current phenomenon may be occurred. To alleviate the disadvantages, diffusion barriers such as Mo, Ti and various metal alloys with hundreds of nanometer-thick or more have been used so far with micrometer size Cu electrode. However, because of the high integration of devices, the Cu electrode might soon be less than a few hundred nanometers, similar to the physical dimension of metal barrier mentioned above. Ultimately, it would be urgent to develop down sized diffusion barriers of less than ten nanometers in order to take advantage of Cu properly.
Self-assembled monolayer (SAM) is a thin film with a few nanometers to control surface of the material. Recently, many researchers study on SAM as a barrier to prevent migration of Cu ions and electrons onto dielectrics such as SiO2. In this study, several functional groups of CH3, SH, CF3, and NH2 SAM diffusion barriers located between IGZO and Cu were investigated in order to not only prevent migration of Cu ions, but also transfer electrons. As a result, there was no hump or abnormal current phenomenon occurring, therefore it was confirmed that the SAMs can prevent Cu ions migration and transfer electrons. The results of the TFT characteristic were measured similarly at whole functional groups, but the SAMs containing carbon in the functional groups such as CH3 and CF3 showed definitely superior performance in the hysteresis measurement.
We also confirmed that a few properties can be controlled by the body group chain length of the SAM verified by the hysteresis, transmission line method (TLM) and SIMS analysis. In other words, the TFT characteristics can be improved or deteriorated with body group chain length of SAM, and we found that it is very important to determine the proper length. This result is expected to have an important impact on the application of Cu electrode in semiconductor devices in the future.