![]() ![]() ![]() (1) Most of the conventional fabrication processes are designed on the basis of the top-down approach, comprising numerous deposition, lithography, and etching steps. The continued downscaling of feature sizes in integrated circuits leads to new challenges in the semiconductor industry. We also found that, as a result of the catalytic activity of the metallic non-growth area, further reactions of inhibitor molecules, such as hydrogenolysis, can play a role in precursor blocking. As the surface saturates, there is a transition from the thermodynamically most favorable adsorption configuration to the sterically most favorable adsorption configuration, which results in a sufficiently dense inhibition layer, such that an incoming precursor molecule cannot fit in between the adsorbed precursor molecules. In addition, RSA simulations showed that the co-presence of two stable adsorption configurations allows for a high surface inhibitor coverage on both Co and Ru surfaces. Further calculations on the aniline-functionalized surfaces show that the aniline inhibitor significantly reduces the interaction of Ti precursor, tetrakis(dimethylamino)titanium, with the non-growth area. DFT reveals two stable adsorption configurations of aniline on the metal surfaces. ![]() Our DFT calculations confirmed that aniline selectively adsorbs on Ru and Co non-growth areas, whereas its adsorption on the SiO 2 growth area is limited to physisorption. In this work, using density functional theory (DFT) and random sequential adsorption (RSA) simulations, we investigated how aniline can effectively block precursor adsorption on specific areas. Recently, aniline (C 6H 5NH 2) was shown to be an effective SMI during the area-selective deposition (ASD) of TiN, giving 6 nm of selective growth on SiO 2 in the presence of Ru and Co non-growth areas. However, the identification of suitable SMIs that yield a high selectivity remains a challenging task. Figure 4 Positively charged nuclei (plural for nucleus) in a cloud of delocalised electrons.Area-selective atomic layer deposition using small-molecule inhibitors (SMIs) involves vapor-phase dosing of inhibitor molecules, resulting in an industry-compatible approach. The electrons are represented by blue spheres that are moving freely to indicate their delocalisation. Each sphere in the second and fourth rows has been shifted horizontally so that it is above the space between adjacent spheres in the first and third rows. ![]() The 16 nuclei are arranged in four staggered rows of four orange spheres that are static. The electrons in the outer shells are represented by blue circles that are moving freely (animated) between the nuclei to indicate their delocalisation.Įach nucleus is represented by an orange sphere with ‘+’ in it. That is, each row of circles in alternate rows are offset by half a circle, to the left or the right, so that they fit in between the circles in the adjacent rows. The nuclei are arranged in staggered rows. Lithium has 3 protons, 4 neutrons and three electrons.Īn animation representing positively charged nuclei in a cloud of delocalised electrons.Įach nucleus is represented by a circle with a plus symbol (‘+’) in it. These positive particles are known as protons and each one carries the same amount of charge as an electron but has the opposite sign, +1.Įach element has its own specific signature in terms of number of protons, neutrons and electrons. This means that the total negative charge of the electrons must be balanced by the total positive charge in these positive particles in the atom, so that the whole atom has a net charge of zero. However, atoms are neutral particles: that is, they carry no net charge. The units do not matter in this case as the ‘−1’ is a comparative amount: one electron has a charge of −1, two electrons a charge of −2 and ten electrons a charge of −10. Conventionally, chemists and physicists speak of an electron as having a charge of −1. Electric charge is the property of matter that causes electrical phenomena. Figure 3 Illustration of shells in a lithium atomĮach electron carries a minute but standard amount of negative electric charge, or charge for short. The outer electron is labelled as having a charge of -1. The nucleus is labelled ‘atomic nucleus containing a proton of charge +1’. Two electrons are shown in the inner shell, and one in the outer. It shows a nucleus (a circle) at the centre, with two concentric rings that represent its electron shells. Figure 3 is a schematic diagram representing a lithium atom. ![]()
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