X-Ray Photoelectron and Rutherford Backscattering Spectroscopy of Silicon Hyperdoped with Selenium

The possibility of surface passivation of silicon by hyperdoping with Se and laser annealing was evaluated by x-ray photoelectron spectroscopy (XPS) and Rutherford backscattering spectroscopy. Silicon layers hyperdoped with Se were formed by Si implantation (140 keV, 6.1∙10¹⁵ cm^–2) followed by pulsed laser annealing (PLA) (λ = 694 nm, W = 2.0 J/cm², τ = 70 ns). The Se concentration in the subsurface region (2.0–2.5 nm) was 0.67% (3.35∙10²⁰ cm^–3). The high Se concentration could be attributed to its accumulation in the subsurface region during PLA to form Si–Se bonds. According to XPS, Se–O bonds did not form in the subsurface implanted layer during PLA. The chosen laser pulse energy density of W = 2 J/cm² allowed high structural perfection (>91%) to be achieved and a high Se concentration (>69%) at the Si lattice sites to be attained.