Defects in HfO 2 dielectric film caused by indium and arsenide diffusion from InAs were investigated. To investigate the dissociation of InAs during post-deposition annealing (PDA) at 600 °C, we analyzed the ratio of the elements on the surface of the oxide layer and the chemical states by using time-of-flight secondary-ion mass spectroscopy and X-ray photoelectron spectroscopy, respectively. In–As bonding was dissociated and In and As atoms were diffused through the HfO 2 layer from InAs. Fortunately, the diffusion and trap density could be controlled by using a 1-nm-thick Al 2 O 3 passivation layer. In addition, we used the nitridation process to control the trap density. We evaluated the thermal and electrical stability of three samples—HfO 2 /InAs, HfO 2 /Al 2 O 3 /InAs, and nitrided HfO 2 /Al 2 O 3 /InAs—by analyzing the change in trap density before and after PDA at 600 °C and the stress-induced leakage current. In conclusion, the passivation layer effectively improved the thermal and electrical stability, whereas the nitridation process using NH 3 gas did not. Moreover, although nitridation could reduce the interfacial defect states, due to structure distortion, it induced the degradation of the device.
Bibliographical noteFunding Information:
Funding: This work was partially supported by an industry–academy joint research program between Samsung Electronics and Yonsei University and by the Korea Institute of Science and Technology (KIST). The authors are grateful for the valuable help in performing the experiments using the 2A beamlines at the Pohang Light Source (PLS).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Physics and Astronomy(all)
- Surfaces and Interfaces
- Surfaces, Coatings and Films