Estudio de la adsorción aleatoria de moléculas inhibidoras en superficies amorfas de óxidos metálicos

Abstract

Debido a la continua miniaturización en la industria de semiconductores, se exigen técnicas de manufactura cada vez más precisas. Como alternativa a la fotolitografía, el area-selective atomic layer deposition (AS-ALD) ha surgido como una técnica capaz de depositar material sobre superficies con control a nivel de ångström. La selectividad de este proceso se basa en el uso de moléculas inhibidoras pequeñas (SMIs) en zonas de no crecimiento para bloquear la adsorción de precursores. Las superficies involucradas pueden ser cristalinas, con un orden regular de sitios activos, o amorfas, que carecen de este orden y son más comunes en sistemas reales. El empaquetamiento de inhibidores se ha estudiado previamente mediante simulaciones de adsorción secuencial aleatoria (RSA), aunque estos estudios se han limitado a superficies cristalinas. Por ende, el objetivo principal de este trabajo es evaluar el efecto de la amorfización de superficies de óxidos metálicos sobre la cobertura y densidad superficial de SMIs mediante simulaciones RSA. Para ello, se generaron superficies amorfas a partir de una superficie cristalina hexagonal de Al2O3, desplazando aleatoriamente sus sitios activos mediante el parámetro desplazamiento permitido (DP). Se construyeron cinco superficies con valores de DP de 0.33, 0.67, 1.00, 1.33 y 1.67 Å, caracterizadas mediante teselación de Voronoi. Posteriormente, se realizaron simulaciones RSA usando representaciones bidimensionales de inhibidores: toy models circulares con radios entre 1 y 10 Å, y footprints de HAc, Hacac y Hthd, obteniéndose datos de cobertura y densidad superficial. Los resultados muestran que, (...). Due to the continuous miniaturization in the semiconductor industry, more precise manufacturing techniques are required. As an alternative to photolithography, area-selective atomic layer deposition (AS-ALD) has emerged as a technique capable of depositing material on surfaces with ångström-level control. A key aspect of this technique is the use of small molecule inhibitors (SMIs) in non-growth areas to prevent precursor adsorption and enhance deposition selectivity. The surfaces where material is deposited can be classified as crystalline, which exhibit an ordered arrangement of active sites, or amorphous, which lack this order and are more common in real systems. Inhibitor packing has been previously studied using random sequential adsorption (RSA) simulations, although these studies have been limited to crystalline surfaces. Therefore, the main objective of this work is to evaluate the effect of surface amorphization of metal oxides on the coverage and surface density of SMIs using RSA simulations. To this end, amorphous surfaces were generated by randomly moving the active sites of a hexagonal crystalline Al2O3 surface, using the allowed displacement (DP) as a control parameter. Five amorphous surfaces with DP values of 0.33, 0.67, 1.00, 1.33, and 1.67 Å were created and characterized through Voronoi tessellation. RSA simulations were performed using two-dimensional representations of inhibitors: circular toy models with radii between 1 and 10 Å and molecular footprints of real SMIs: HAc, Hacac, and Hthd. From these simulations, coverage and surface density data were obtained in order to evaluate the effect of surface amorphization. The results show that, (...).