Effect of the thermal annealing temperature on the luminescent and morphological properties of silicon rich oxide bilayer structures.

This work studies the effect of the thermal annealing temperature on the optical and morphological properties of SR$\mathrm{O}_{\mathrm{x}}$/SR$\mathrm{O}_{\mathrm{y}}$ bilayer structures when the SR$\mathrm{O}_{\mathrm{y}}$ contains a high silicon excess. SR$\mathrm{O}_{\mathrm{x}}$/SR$\mathrm{O}_{\mathrm{y}}$ bilayer structures were deposited by low pressure chemical vapor deposition and then thermally annealed at temperatures ranging from 900-1100 0C. In addition, $\mathrm{S}\mathrm{R}\mathrm{O}_{\mathrm{x}}$ and SR$\mathrm{O}_{\mathrm{y}}$ monolayers were deposited for comparison. The refraction index and the average roughness decrease when the thermal annealing temperature increases as a result of structural changes within the SR$\mathrm{O}_{\mathrm{x}}$/SR$\mathrm{O}_{\mathrm{y}}$ bilayers. A two-fold improvement in the photoluminescence (PL) intensity (65 to 136 a.u/nm) was obtained as the annealing temperature is reduced from 1100 to 1050°c. A relationship between PL emission and surface morphology was analyzed.