Passivation of n- and p-Type Silicon Surfaces With Spray-Coated Sol-Gel Silicon Oxide Thin Film

Thermally grown SiO
₂
is widely used for silicon surface passivation in solar cells and other applications due to excellent interfacial properties. SiO
₂
films with thickness in the range of 17 nm deposited by industrially viable spray-coating technique on both nand p-type silicon are reported. Low values of interface state density of 1.4 × 10
¹⁰
cm
^-2
eV
^-1
on n-type and 2.0 × 10
¹⁰
cm
^-2
eV
^-1
on p-type were achieved. Fixed oxide charges in the range of 7.1-9.4 × 10
¹¹
cm
^-2
and 3.9-6.5 × 10
¹¹
cm
^-2
on nand p-type, respectively, are obtained. Excellent passivation results in the effective surface recombination velocity of 0.97 cms
^-1
and 8.07 cms
^-1
at minority carrier concentration of 10
¹⁵
cm
^-3
on nand ptype Czochralski silicon, respectively, without the use of capping layer. SiO
₂
film exhibits dielectric breakdown field strength of 4.3 MVcm
^-1
and 5.6 MVcm
^-1
and leakage current density of 2.2 × 10
^-8
Acm
^-2
and 1.1 × 10
^-8
Acm
^-2
at 1 MVcm
^-1
on nand p-type silicon, respectively. These values are superior to sol-gelbased SiO
₂
films reported previously and are comparable to or better than those reported for other methods for the growth or deposition of SiO
₂
on silicon. Amorphous nature of the film is validated by high-resolution transmission electron microscopy (TEM). The X-ray photoelectron spectroscopy (XPS) analysis shows nearly stoichiometric SiO
_x
film.