Browsing by Author "Kim, YongJoo"

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    Area-selective atomic layer deposition on 2D monolayer lateral superlattices
    (Springer Nature, 2024) Park, Jeongwon; Kwak, Seung Jae; Kang, Sumin; Oh, Saeyoung; Shin, Bongki; Noh, Gichang; Kim, Tae Soo; Kim, Changhwan; Park, Hyeonbin; Oh, Seung Hoon; Kang, Woojin; Hur, Namwook; Chai, Hyun-Jun; Kang, Minsoo; Kwon, Seongdae; Lee, Jaehyun; Lee, Yongjoon; Moon, Eoram; Shi, Chuqiao; Lou, Jun; Lee, Won Bo; Kwak, Joon Young; Yang, Heejun; Chung, Taek-Mo; Eom, Taeyong; Suh, Joonki; Han, Yimo; Jeong, Hu Young; Kim, YongJoo; Kang, Kibum
    The advanced patterning process is the basis of integration technology to realize the development of next-generation high-speed, low-power consumption devices. Recently, area-selective atomic layer deposition (AS-ALD), which allows the direct deposition of target materials on the desired area using a deposition barrier, has emerged as an alternative patterning process. However, the AS-ALD process remains challenging to use for the improvement of patterning resolution and selectivity. In this study, we report a superlattice-based AS-ALD (SAS-ALD) process using a two-dimensional (2D) MoS2-MoSe2 lateral superlattice as a pre-defining template. We achieved a minimum half pitch size of a sub-10 nm scale for the resulting AS-ALD on the 2D superlattice template by controlling the duration time of chemical vapor deposition (CVD) precursors. SAS-ALD introduces a mechanism that enables selectivity through the adsorption and diffusion processes of ALD precursors, distinctly different from conventional AS-ALD method. This technique facilitates selective deposition even on small pattern sizes and is compatible with the use of highly reactive precursors like trimethyl aluminum. Moreover, it allows for the selective deposition of a variety of materials, including Al2O3, HfO2, Ru, Te, and Sb2Se3.
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    Host-Guest Self-assembly in Block Copolymer Blends
    (Springer Nature, 2013) Park, Woon Ik; Kim, YongJoo; Jeong, Jae Won; Kim, Kyungho; Yoo, Jung-Keun; Hur, Yoon Hyung; Kim, Jong Min; Thomas, Edwin L.; Alexander-Katz, Alfredo; Jung, Yeon Sik
    Ultrafine, uniform nanostructures with excellent functionalities can be formed by self-assembly of block copolymer (BCP) thin films. However, extension of their geometric variability is not straightforward due to their limited thin film morphologies. Here, we report that unusual and spontaneous positioning between host and guest BCP microdomains, even in the absence of H-bond linkages, can create hybridized morphologies that cannot be formed from a neat BCP. Our self-consistent field theory (SCFT) simulation results theoretically support that the precise registration of a spherical BCP microdomain (guest, B-b-C) at the center of a perforated lamellar BCP nanostructure (host, A-b-B) can energetically stabilize the blended morphology. As an exemplary application of the hybrid nanotemplate, a nanoring-type Ge2Sb2Te5 (GST) phase-change memory device with an extremely low switching current is demonstrated. These results suggest the possibility of a new pathway to construct more diverse and complex nanostructures using controlled blending of various BCPs.