TY - JOUR
T1 - Hydrogen-plasma etching of hydrogenated amorphous silicon
T2 - A study by a combination of spectroscopic ellipsometry and trap-limited diffusion model
AU - Kaïl, F.
AU - Fontcuberta i Morral, A.
AU - Hadjadj, A.
AU - Roca i Cabarrocas, P.
AU - Beorchia, A.
PY - 2004/2/21
Y1 - 2004/2/21
N2 - The kinetics of etching hydrogenated amorphous silicon by a hydrogen plasma has been studied by in-situ spectroscopic ellipsometry measurements. The formation of a hydrogen-rich sublayer is clearly emphasized. Its thickness increases from 7 to 27 nm when the temperature during the hydrogen-plasma treatment is raised from 100 to 250°C. This effect is interpreted by solving the differential equation for trap-limited hydrogen diffusion through a mobile surface. By assigning the thickness of this sublayer to the mean diffusion distance of hydrogen we determined values of the effective diffusion coefficient of hydrogen higher than 10-14cm2s -1 with an activation energy of 0.22 eV. The density of hydrogen traps is found to decrease from 7.3 × 1018 to 4.5 × 1017cm-3 as the temperature of the hydrogen treatment increases from 100 to 250°C with an activation energy of 0.43 eV. This effect is interpreted by a thermal equilibrium involving hydrogen transitions between shallow states and hydrogen-trapping sites.
AB - The kinetics of etching hydrogenated amorphous silicon by a hydrogen plasma has been studied by in-situ spectroscopic ellipsometry measurements. The formation of a hydrogen-rich sublayer is clearly emphasized. Its thickness increases from 7 to 27 nm when the temperature during the hydrogen-plasma treatment is raised from 100 to 250°C. This effect is interpreted by solving the differential equation for trap-limited hydrogen diffusion through a mobile surface. By assigning the thickness of this sublayer to the mean diffusion distance of hydrogen we determined values of the effective diffusion coefficient of hydrogen higher than 10-14cm2s -1 with an activation energy of 0.22 eV. The density of hydrogen traps is found to decrease from 7.3 × 1018 to 4.5 × 1017cm-3 as the temperature of the hydrogen treatment increases from 100 to 250°C with an activation energy of 0.43 eV. This effect is interpreted by a thermal equilibrium involving hydrogen transitions between shallow states and hydrogen-trapping sites.
U2 - 10.1080/14786430310001635440
DO - 10.1080/14786430310001635440
M3 - Article
AN - SCOPUS:10744225826
SN - 1478-6435
VL - 84
SP - 595
EP - 609
JO - Philosophical Magazine
JF - Philosophical Magazine
IS - 6
ER -