Enhanced Area-Selective Deposition via NH₃ Plasma Treatment in Atomic Layer Deposition for Si/TiN Substrates

This study explores the efficacy of NH₃ plasma treatment in enhancing the area-selective deposition (ASD) of cobalt films on Si/TiN-patterned substrates by using a modified atomic layer deposition (ALD) process. The introduction of NH₃ plasma into the precursor-inhibition ALD (PI-ALD) cycle significantly suppresses Co adsorption on Si substrates while promoting growth on TiN substrates. This behavior is attributed to the formation of NH_x-terminated surfaces on Si, which inhibit precursor chemisorption, and the removal of oxidized species on TiN, enhancing adsorption. Surface analyses confirm that NH₃ plasma treatment does not deteriorate the substrate's roughness, crystallinity, or composition but instead improves the film's metallic nature. The PI-ALD process achieves high selectivity and precision, confirming its potential for scalable ASD applications without the need for additional inhibitors.