Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide

Abstract

Atomic layer deposition (ALD) enables the ultrathin high-quality oxide layers that are central to all modern metal-oxide-semiconductor circuits. Crucial to achieving superior device performance are the chemical reactions during the first deposition cycle, which could ultimately result in atomic-scale perfection of the semiconductor–oxide interface. Here, we directly observe the chemical reactions at the surface during the first cycle of hafnium dioxide deposition on indium arsenide under realistic synthesis conditions using photoelectron spectroscopy. We find that the widely used ligand exchange model of the ALD process for the removal of native oxide on the semiconductor and the simultaneous formation of the first hafnium dioxide layer must be significantly revised. Our study provides substantial evidence that the efficiency of the self-cleaning process and the quality of the resulting semiconductor–oxide interface can be controlled by the molecular adsorption process of the ALD precursors, rather than the subsequent oxide formation.

Upgrade of the SPECIES beamline at the MAX IV Laboratory

“…APXPS is a very convenient tool for studying ALD processes since the pressure and temperature ranges needed for optimal growth are within the ranges of the typical AP cells in use at SPECIES. APXPS has been recently demonstrated as a very powerful tool for in situ and operando investigations into the first half-cycles of the ALD processes (Head et al, 2016;Timm et al, 2018;Temperton et al, 2019;D'Acunto et al, 2020).…”

Synchronizing gas injections and time-resolved data acquisition for perturbation-enhanced APXPS experiments

“…Thicknesses of these films can be controlled accurately and simply by the number of deposition cycles repeated. APXPS measurements have emerged as a valuable source of fundamental information about the surface reactions involved in ALD [58][59][60][61] . We have used the pulsed valve system together with the RPi electronics to automate the pulsing of the precursor gases in order to study ALD processes in-situ using APXPS.…”

Study on the regulation of polythiophene whiskers by electric field induction and the anisotropy of the film surface

“…10 Due to these properties, surfaces can directionally transport or collect liquid efficiently while preventing contamination from the liquid. This has good application prospects in self-cleaning, [11][12][13] directional adhesion 14 and water collection [15][16][17] such as self-cleaning glass, micro-chemical reactors, industrial oil extraction, waterproof pipeline transportation etc. [18][19][20][21][22][23][24] Assembling soft matter such as conjugated polymers into ordered structures is one of the methods of fabricating anisotropic surfaces.…”