Impact of Pregrown SiO_x on the Carrier Selectivity and Thermal Stability of Molybdenum-Oxide-Passivated Contact for Si Solar Cells

Thin SiO_x interlayers are often formed naturally during the deposition of transition metal oxides on silicon surfaces due to interfacial reaction. The SiO_x 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_x interlayer by the introduction of pregrown high-quality SiO_x which also inhibits the formation of low-quality SiO_x from the metal-oxide deposition process. This work demonstrates that a high-quality pregrown SiO_x can reduce the interfacial reaction and results in a more stoichiometric MoO_x with improved surface passivation and thermal stability linked to its lower D_it. Detailed experimental data on carrier selectivity, carrier transport efficiency, annealing stability up to 250 °C, and in-depth material analysis are presented.