Study on surface passivation by YZO/AlO<inf>x</inf> stacking double layer for crystalline Si solar cells

Abstract

We investigated stacking double layer structure, the Y 203-Zr02 composite film (YZO) on AIO" for the field effect passivation with high negative fixed charge densities on p-type Si. The composition spread YZO films were deposited at room temperature by using combinatorial sputtering technique. The fixed charge densities were extracted from the flat band voltage shift in the capacitance-voltage characteristics. The as-deposited Zr02 film incorporated with 15% Y 203 stacking on the ALD AIOx structure showed the highest negative fixed charge of -1.9 x 10 1 2 cm· 2 . The field effect passivation can be controlled by the negative fixed charges in the YZO film depending on the composition and dipole uniformly formed at AIOx/Si interface. After annealing in the oxygen atmosphere, passivation properties deteriorated caused by the AI diffusion at the YZO/AIOx interface. Index Terms -stacking double layer, combinatorial technique, capacitance-voltage characteristics, field effect passivation, negative fixed charge density.

Investigation of new stacking surface passivation structures with interfacial tuning layers on p-type crystalline silicon

“…12) We also verified that the negative fixed charges originated in the film; therefore, they increased with increasing film thickness. 13) On the other hand, the Al 2 O 3 film, which is well known as a superior passivation film for p-type Si, has an electrical dipole at the interface between SiO 2 and Al 2 O 3 provides similar desired effects as negative fixed charges. [14][15][16][17][18][19][20][21][22] This is confirmed, for example, by the result that the negative fixed charge formation was completed with Al 2 O 3 thicknesses less than 10-20 nm and further thickness increase showed field effect saturation.…”