Formation, nature, and stability of the arsenic-silicon-oxygen alloy for plasma doping of non-planar silicon structures

We demonstrate stable arsenic-silicon-oxide film formation during plasma doping of arsenic into non-planar silicon surfaces through investigation of the nature and stability of the ternary oxide using first principles calculations with experimental validations. It is found that arsenic can be co-mingled with silicon and oxygen, while the ternary oxide exhibits the minimum energy phase at x ≈ 0.3 in As_xSi_1-xO_2-0.5x. Our calculations also predict that the arsenic-silicon-oxide alloy may undergo separation into As-O, Si-rich As-Si-O, and Si-O phases depending on the composition ratio, consistent with experimental observations. This work highlights the importance of the solid-state chemistry for controlled plasma doping.