Lee Sangbong, Kang Yun-Ho, Kim Min-Sik, Lee Hyerin, Cho Yeong-Ho, Kim Minsu, Yoon Tae-Sik, Kim Hyun-Mi, Kim Ki-Bum
Department of Materials Science and Engineering, Seoul National University, Seoul 08826, Republic of Korea.
Department of Materials Science and Engineering, Myongji University, Yongin, Gyeonggi-do 17058, Republic of Korea.
ACS Appl Mater Interfaces. 2020 Sep 2;12(35):39372-39380. doi: 10.1021/acsami.0c07540. Epub 2020 Aug 20.
This study reports on the effect of a bilayer period on the growth behavior, microstructure evolution, and electrical properties of atomic layer deposition (ALD) deposited In-Zn-O (IZO) films, fixing the ALD cycle ratio of In-O/Zn-O as 9:1. Here, the bilayer period is defined as the total number of ALD cycles in one supercycle of In-O and Zn-O by alternately stacking Zn-O and In-O layers at a temperature of 220 °C. IZO films with a bilayer period from 10 to 40 cycles, namely, IZO[In-O/Zn-O = 9:1] to IZO[36:4], result to form an amorphous phase with a resistivity of 4.94 × 10 Ω·cm. However, by increasing the bilayer period above 100 cycles, the IZO films begin to form a mixed amorphous-nanocrystalline microstructure, resulting from the limited intermixing at the interfaces. Concomitantly, the overall film resistivity is considerably increased with a simultaneous decrease in both the carrier mobility and the concentration. These results not only reveal the importance of the bilayer period in designing the ALD stacking sequence in the ALD-IZO, but also provide the possibility of forming various multilayered materials with different electrical properties.
