Impact of Pregrown SiO_<i>x</i> on the Carrier Selectivity and Thermal Stability of Molybdenum-Oxide-Passivated Contact for Si Solar Cells

Abstract

Thin SiO_<i>x</i> interlayers are often formed naturally during the deposition of transition metal oxides on silicon surfaces due to interfacial reaction. The SiO_<i>x</i> layer, often only several atomic layers thick, becomes the interface between the Si and deposited metal oxide and can therefore influence the electrical properties and thermal stability of the deposited stack. This work explores the potential benefits of controlling the properties of the SiO_<i>x</i> interlayer by the introduction of pregrown high-quality SiO_<i>x</i> which also inhibits the formation of low-quality SiO_<i>x</i> from the metal-oxide deposition process. This work demonstrates that a high-quality pregrown SiO_<i>x</i> can reduce the interfacial reaction and results in a more stoichiometric MoO_<i>x</i> with improved surface passivation and thermal stability linked to its lower <i>D</i>_it. Detailed experimental data on carrier selectivity, carrier transport efficiency, annealing stability up to 250 °C, and in-depth material analysis are presented.