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InGaZnO (IGZO)-based thin-film transistors and selector diodes are increasingly investigated for a broad range of applications such as high-resolution displays, high-density memories, and high-speed computing. However, its potential to be a key material for next-generation devices is strongly contingent on developing patterning processes with minimal damage at nanoscale dimensions. IGZO can be etched using CH 4 -based plasma. Although the etched by-products are volatile, there remains a concern that passivation─an associated effect arising from the use of a hydrocarbon etchant─may inhibit the patterning process. However, there has been limited discussion on the CH 4 -based etching of IGZO and the subsequent patterning challenges arising with pitch scaling (<200 nm). In this work, we systematically investigate dry chemical etching schemes to pattern an IGZO film into densely packed nanostructures using CH 4 . Straight IGZO lines, ∼45 nm in width at a pitch of ∼135 nm, are produced by employing the traditional reactive ion etching method. While the passivating effect of CH 4 does not impede the etching process, any further shrinkage of feature and pitch dimensions amplifies reactive ion etching-induced damage in the form of profile distortion and residue redeposition. We show that this is efficiently addressed via atomic layer etching (ALE) of IGZO with CH 4 using a pulsed plasma. The unique combination of ALE and plasma pulsing enables controlled reduction of ion-assisted sputtering and redeposition of residues on the patterned IGZO features. This approach is highly scalable and is successfully applied here to achieve well-separated IGZO lines, with critical dimensions down to ∼20 nm at a dense pitch of ∼36 nm. These lines exhibit steep profiles (∼80°) and no undesirable change in IGZO composition post-patterning. Finally, ALE of IGZO under pulsed plasma, reproduced on 300 mm wafers, highlights its suitability in large-scale manufacturing for the intended applications.

An understanding of the factors influencing the thermal stability of ultrathin carbon overcoats (COCs) is crucial for their application in heat-assisted magnetic recording (HAMR) at densities ≥ 1 Tb/in(2). Two types of non-hydrogenated ultrathin (∼1.5 nm) COCs were investigated after being subjected to laser-induced localized heating (at temperatures > 700 K) as envisaged in HAMR. Filtered cathodic vacuum arc (FCVA)-processed carbon with tuned C(+) ion energies of 350 eV followed by 90 eV provides significantly higher sp(3) C-C hybridization than magnetron sputter deposition even at very low thicknesses of ∼1.5 nm. As a result, the FCVA-deposited ultrathin carbon overcoats displayed excellent thermal stability along with improved wear and corrosion resistance. On the other hand, the sputtered carbon exhibited carbon loss and topographical and structural changes after laser irradiation owing to lower sp(3) hybridization. Therefore, this study highlights the pivotal role of carbon microstructure, primarily sp(3) hybridization, in non-hydrogenated carbon overcoats to maintain excellent thermal stability during the recurring high-temperature cycles in a HAMR process.