Controlled bond formation between chemical vapor deposition Si and ultrathin SiO2 layers

This article reports that chemically active sites on ${\mathrm{SiO}}_2$ surfaces can be either passivated or introduced intentionally by treating them in a proper chlorosilane gas, ${\mathrm{SiH}}_n{\mathrm{Cl}}_{\text{4−n}}\text{\hspace{0.05em}(n=0,1,2).}$ Our experiments of Si chemical vapor deposition on ${\mathrm{SiO}}_2$ -covered Si have shown that Si deposition is suppressed on ${\mathrm{SiCl}}_4$ - and ${\mathrm{SiHCl}}_3$ -treated samples, while an ${\mathrm{SiH}}_{\mathrm{2}}{\mathrm{Cl}}_2$ treatment drastically enhances Si nucleation. Thus, the chlorosilane treatment is a unique way for us to control the interface bonds between the ${\mathrm{SiO}}_2$ surface and the Si deposits on it. We also demonstrate resistless selective-area deposition using a ${\mathrm{SiHCl}}_3$ -treated ultrathin ${\mathrm{SiO}}_2$ mask layer. Patterns are defined on the mask surface by direct electron-beam irradiation which induces Cl desorption thereby forming chemically reactive surface defects.