Self-aligned patterning of tantalum oxide on Cu/SiO2 through redox-coupled inherently selective atomic layer deposition.

Atomic-scale precision alignment is a bottleneck in the fabrication of next-generation nanoelectronics. In this study, a redox-coupled inherently selective atomic layer deposition (ALD) is introduced to tackle this challenge. The 'reduction-adsorption-oxidation' ALD cycles are designed by adding an in-situ reduction step, effectively inhibiting nucleation on copper. As a result, tantalum oxide exhibits selective deposition on various oxides, with no observable growth on Cu. Furthermore, the self-aligned TaOx is successfully deposited on Cu/SiO2 nanopatterns, avoiding excessive mushroom growth at the edges or the emergence of undesired nucleation defects within the Cu region. The film thickness on SiO2 exceeds 5 nm with a selectivity of 100%, marking it as one of the highest reported to date. This method offers a streamlined and highly precise self-aligned manufacturing technique, which is advantageous for the future downscaling of integrated circuits.

Promotional Effect of H2 Pretreatment on the CO PROX Performance of Pt1/Co3O4: A First-Principles-Based Microkinetic Analysis.

Atomic Pt studded on cobalt oxide is a promising catalyst for CO preferential oxidation (PROX) dependent on its surface treatment. In this work, the CO PROX reaction mechanism on Co3O4 supported single Pt atom is investigated by a comprehensive first-principles based microkinetic analysis. It is found that as synthesized Pt1/Co3O4 interface is poisoned by CO in a wide low temperature window, leading to its low reactivity. The CO poisoning effect can be effectively mitigated by a H2 prereduction treatment, that exposes Co ∼ Co dimer sites for a noncompetitive Langmuir-Hinshelhood mechanism. In addition, surface H atoms assist O2 dissociation via "twisting" mechanism, avoiding the high barriers associated with direct O2 dissociation path. Microkinetic analysis reveals that the promotion of H-assisted pathway on H2 treated sample helps improve the activity and selectivity at low temperatures.

Inherently Area-Selective Atomic Layer Deposition of Manganese Oxide through Electronegativity-Induced Adsorption.

Manganese oxide (MnOx) shows great potential in the areas of nano-electronics, magnetic devices and so on. Since the characteristics of precise thickness control at the atomic level and self-align lateral patterning, area-selective deposition (ASD) of the MnOx films can be used in some key steps of nanomanufacturing. In this work, MnOx films are deposited on Pt, Cu and SiO2 substrates using Mn(EtCp)2 and H2O over a temperature range of 80-215 °C. Inherently area-selective atomic layer deposition (ALD) of MnOx is successfully achieved on metal/SiO2 patterns. The selectivity improves with increasing deposition temperature within the ALD window. Moreover, it is demonstrated that with the decrease of electronegativity differences between M (M = Si, Cu and Pt) and O, the chemisorption energy barrier decreases, which affects the initial nucleation rate. The inherent ASD aroused by the electronegativity differences shows a possible method for further development and prediction of ASD processes.

Noninvasive genotyping of 9 Y-chromosome specific STR loci using circulatory fetal DNA in maternal plasma by multiplex PCR.

BACKGROUND: Human Y-Chromosome specific STR (Y-STR) has now become a useful loci in casework. However, noninvasive genotyping of multiple Y-STR loci and its application in prenatal genetic diagnosis haven't been reported. The purpose of this study is to develop a Y-STR multiplex PCR amplification system that is suitable for the amplification of short-sized templates of circulatory male fetal DNA and use the established multiplex in noninvasive prenatal genetic diagnosis and its further applications in forensic casework. METHODS: On the basis of the characteristic of circulatory fetal DNA in maternal plasma, we selected 9 Y-STR loci in which the allele size was less than 180 bp in length and developed two multiplexes that allowed fluorescent genotyping of 9 Y-STR loci simultaneously. These Y-STR loci include two trinucleotide repeats (DYS426 and DYS388) and seven tetranucleotide repeats (DYS393, DYS460, H4; DYS391, DYS389 I, DYS456 and DYS458). Sixty-four pairs of plasma DNA samples from pregnant women and genomic DNA samples from their husbands were detected by our method. RESULTS: As a result, an average of 7.3 Y-STR specific alleles was detected in each of the 30 plasma DNA samples from pregnancies with male fetuses. However, none of these 9 Y-STR specific alleles was detected in 34 plasma samples from pregnant women carrying female babies. The chances of detecting Y-STR alleles ranged from 66.7 to 93.3%. Fifty-eight haplotypes were detected in 64 unrelated Chinese male individuals; haplotype diversity was 0.9966. This highly polymorphic Y-STR multiplex has greatly improved the chances of detecting the Y-STR allele. CONCLUSIONS: This assay provides a sensitive, accurate and efficient method for noninvasive prenatal genetic diagnosis and forensic casework.