Thermal stability of L1₀-FePt nanodots patterned by self-assembled block copolymer lithography

Abstract

Arrays of 14 nm thick L1-FePt nanodots with diameter of 27 nm and center-to-center spacing of 39 nm were produced by block copolymer patterning of an FePt film and their magnetic reversal and thermal stability were characterized. A self-assembled polystyrene-b-polydimethylsiloxane diblock copolymer film was used as a lithographic mask and a pattern transfer process based on ion beam etching and rapid thermal annealing of the sputtered FePt film was developed. The dot arrays exhibited perpendicular magnetic anisotropy with K = 4.8 × 10 erg cm and a saturation magnetization of 960 emu cm. First order reversal curves indicate a softer magnetic component attributed to the ion-milled material at the edges of the dots. The switching volume and the thermal stability were obtained from relaxation measurements and DC demagnetization curves. Micromagnetic simulations reproduce the magnetic domain structure obtained for the continuous and patterned FePt thin film.

Controlled Magnetic Anisotropy in Single Domain Mn-doped Biosynthesized Nanoparticles

“…Below these temperatures, the kink disappears. The presence of a kink is commonly related to the existence of two magnetic phases but, and as will be shown later, the disappearance of the kink at low temperatures suggests a different origin. Finally, in comparison with the undoped magnetosomes, the ZFC/FC- M ( H ) curves of Mn(100) and Mn(480) samples exhibit a reduction of the coercivity in the whole range of temperatures (≈25 and ≈40%, respectively), in agreement with previous reports in the bibliography. ,, …”

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO2 Thin Films by Vapor-Phase Infiltration

“…Gate voltage scaling at these dimensions necessitates state-of-the-art architectures beyond FinFETs such as gate-all-around FET technology, leading to further integration complexity 4 . Approaches complimenting photolithography include nanoimprint lithography 5,6 , block copolymer lithography [7][8][9][10][11][12][13][14] and, recently, area selective deposition (ASD) [15][16][17] . Such methods are favorable in enabling future device integration and help alleviate fabrication demands, e.g.…”

“…Continued miniaturization of semiconductor devices has led to cost and integration issues which challenge the manufacture of a 3 nm node as envisaged by semiconductor foundries for 2023. , Gate voltage scaling at these dimensions necessitates state-of-the-art architectures beyond fin field-effect transistors (FETs) such as the gate-all-around FET technology, leading to further integration complexity . Approaches complimenting photolithography include nanoimprint lithography, , block copolymer lithography, − and, recently, area-selective deposition (ASD). − Such methods are favorable in enabling future device integration and help alleviate fabrication demands, for example, litho-etch–litho-etch.…”

Optimizing Polymer Brush Coverage To Develop Highly Coherent Sub-5 nm Oxide Films by Ion Inclusion

“…The continual aggressive miniaturization of semiconductor devices with critical dimensions approaching 5 nm has led to cost and integration challenges . Novel methods to compliment optical lithography (namely, i193 and EUV) include block copolymer − (BCP) lithography, nanoimprint lithography, , and, more recently, area-selective deposition (ASD). These methods are potential candidates for integration into future fabrication and the possibility of selective inclusion of materials; for example, metal, metal oxides, and dielectrics may afford a direct means of generating material patterns.…”