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It is well known that high line-edge roughness (LER) and line-width roughness (LWR) are one of the key problems hindering utilization of extreme ultraviolet lithography (EUVL) in fabrication of semiconductor devices at advanced technology nodes where pattern with sub-20 nm half pitch lines and spaces is required. Sequential infiltration synthesis (SIS) has never been used before in lithography for line-edge roughness mitigation, but this concept has proved its value for 14 nm half pitch block copolymer lines formed by directed self-assembly. During this process an inorganic scaffold is being deposited inside the resist material after performing several sequential infiltration cycles with metal-organic precursor and its oxidizing agent. Etching in oxygen atmosphere after is required to transform former resist pattern into metal oxide one and improve (up to 40%) the pattern roughness. In this paper, for the first time we demonstrate feasibility of sequential infiltration synthesis (SIS) for smoothing of EUV resist lines.

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We present an alternative approach to grow thick GaN single crystalline layers from Ga vapour, transported by an N 2 carrier gas flow, and from nitrogen, excited very near the substrate by 2.45 GHz microwaves at pressure in the 200-800 mbar range. Crystal growth requires high stability of process parameters, especially of plasma operation. A major challenge arose from temperature dependent changes in cavity resonance. Optical emission spectroscopy (OES) was used for plasma characterization while the grown layers were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD).

The prospects of a control for a novel gallium nitride pseudo-halide vapor phase epitaxy (PHVPE) with HCN were thoroughly analyzed for hydrocarbons-NH3-Ga gas phase on the basis of quantum chemical investigation with DFT (B3LYP, B3LYP with D3 empirical correction on dispersion interaction) and ab-initio (CASSCF, coupled clusters, and multireference configuration interaction including MRCI+Q) methods. The computational screening of reactions for different hydrocarbons (CH4, C2H6, C3H8, C2H4, and C2H2) as readily available carbon precursors for HCN formation, potential chemical transport agents, and for controlled carbon doping of deposited GaN was carried out with the B3LYP method in conjunction with basis sets up to aug-cc-pVTZ. The gas phase intermediates for the reactions in the Ga-hydrocarbon systems were predicted at different theory levels. The located π-complexes Ga…C2H2 and Ga…C2H4 were studied to determine a probable catalytic activity in reactions with NH3. A limited influence of the carbon-containing atmosphere was exhibited for the carbon doping of GaN crystal in the conventional GaN chemical vapor deposition (CVD) process with hydrocarbons injected in the gas phase. Our results provide a basis for experimental studies of GaN crystal growth with C2H4 and C2H2 as auxiliary carbon reagents for the Ga-NH3 and Ga-C-NH3 CVD systems and prerequisites for reactor design to enhance and control the PHVPE process through the HCN synthesis.