| AVS 64th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology Division | Thursday Sessions |
| Session NS-ThP |
| Session: | Nanometer-scale Science and Technology Poster Session |
| Presenter: | DooHyeon Cho, Inha University, Republic of Korea |
| Authors: | D.H. Cho, Inha University, Republic of Korea J.S. Choi, Inha University, Republic of Korea J.Y. Lee, Inha University, Republic of Korea C.W. Chung, Inha University, Republic of Korea |
| Correspondent: | Click to Email |
Dynamic random access memory device has been commercially sucessful. However this device has disadvantages such as volatility and scaling problem. Spin transfer torque magnetic random access memory(STT-MRAM) has been recieved a great attention as the next-generation memory device owing to the advantages such as non-volatility, high density, unlimited endurance and low operating voltage[1]. The STT-MRAM devices are composed of magnetic tunnel junction stacks (MTJs) and CMOS. As the dimension of MTJs is decreased, perpendicular magnetic anisotropy (PMA) is necessary for high density MRAM. Therefore, the MTJs comprised of multilayers incluing CoFeB thin films should be fabricated in nanometer-scale dimension for PMA [2]. In order to realize this demand for high density MRAMs, the magnetic thin films such as CoFeB, CoPt, PtMn and so on should be patterned in nanometer-scale.
In the previous studies, micrometer-scale patterned CoFeB thin films showed relatively good etch profiles using CH3OH, CH3COOH and CH4/O2/Ar [3,4,5]. In this study, the etch characteristics of nanometer-scale patterned CoFeB thin films using CH4/O2/Ar gas mixture under pulse-modulated plasma were investigated. The main parameters in pulsed-modulated plasma, which are on-off duty ratio and pulse frequency, were applied to investigate the etch characterisitic of CoFeB thin films. Finally, high degree of anisotropy of the etched CoFeB films with 70 x 70 nm2 patterns were obtained and the etch mechanism also was examined using optical emission spectroscopy, X-ray photoelectron spectroscopy and TEM micrographs.
[1] S. Ikeda, K. Miura, H. Yamamoto, K. Mizunuma, H. D. Gan, M. Endo, S. Kanai, J. Hayakawa, F. Matsukura, H. Ohno, Nature Materials 9, 721 (2010).
[2] W. X. Wang, Y. Yang, H. Naganuma, Y. Ando, R. C. Yu and X. F. Han, Appl. Phys. Lett. 99, 012502 (2011).
[3] Yu Bin Xiao, Eun Ho Kim, Seon Mi Kong, Chee Won Chung, Thin Solid Films 519, 6673 (2011)
[4] Adrian Adalberto Garay, Su Min Hwang, Ji Hyun Choi, Byoung Chul Min, Chee Won Chung, Vacuum 119, 151 (2015)
[5] Eun Ho Kim, Tea Young Lee, Byoung Chul Min, Chee Won Chung, Thin Solid Films 521, 216 (2012)