Post Deposition Annealing Temperature Optimization for Sol-gel Spray-coated SiO2 Film for P-type Cz Si Surface Passivation

Sol-gel SiO
2
film is deposited via low-temperature spray-coating technique using a custom-designed spray-coater tool. Spray-coated film has been subjected to post deposition annealing (PDA) in O
2
ambient. Effect of PDA temperature on the electrical properties of the SiO
2
film is studied by fabricating MOS capacitors. Optimization of PDA temperature is performed in terms of interface state density (
$\mathrm{D}_{it}$
), fixed oxide charge density (
$\mathrm{Q}_{f}$
) and leakage current density (
$\mathrm{J}_{leak}$
). The temperature is optimized to 650°C at which
$\mathrm{D}_{it},\ \mathrm{Q}_{f}$
, and
$\mathrm{J}_{leak}$
in the range of
$2.0 - 6.0\times 10^{10}\ \text{cm}^{-2}\text{eV}^{-1},\ 3.9-6.5\times 10^{11} \text{cm}^{-2}$
, and
$1.12-3.96\times 10^{-8}\ \mathrm{A}\ \text{cm}^{-2}$
, respectively are achieved. At 650°C, the best
$\mathrm{D}_{it}$
obtained is
$2.0\times 10^{10}\ \text{cm}^{-2}\text{eV}^{-1}$
, which lies at an energy level of 0.263 eV from valence band edge in the bandgap. Passivation study performed at this optimized temperature gives surface recombination velocity of 8 cm sec
⁻¹
on p type Cz Si substrate.