Silicio policristalino dopado depositado en forma de láminas delgadas sobre sustratos de vidrio a partir de triclorosilano

BENVENUTO, A. G.; BUITRAGO, R. H.; LONGEAUD, C.; SCHMIDT, J. A.

Santa Fe

Congreso; Congreso Internacional de Metalurgia y Materiales IBEROMAT-SAM-CONAMET-2014; 2014

Sociedad Argentina de Materiales

In this work we use atmospheric pressure chemical vapor deposition (AP-CVD) to deposit thin layers of polycrystalline silicon (poly-Si) on glass substrates. The batch-type hot-wall CVD reactor uses SiHCl3 as precursor, H2 as carrier and reaction gas, BBr3 as p-type dopant, and PCl3 as n-type dopant. We use as a substrate a commercial aluminosilicate float glass, which resists the deposition temperature of 850 °C. The films obtained are homogeneous and have good adhesion to the substrate. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to observe the surface and cross section of the samples. For p-type doped samples we observed a columnar structure appropriate for electrical conduction in photovoltaic cells, whereas X-ray diffraction reveals a strong (2 2 0) preferential orientation. On the other hand, the n-type samples lack of columnar structure or preferential orientation, which shows that phosphorus inhibits such growth regime. The dark conductivity measurements as a function of temperature show that films may be obtained with activation energies between 0.61 and 0.03 eV. Meanwhile, Hall effect measurements show that the layers can be grown intrinsic, n-type or p-type depending on the dopant added. In conclusion, our results demonstrate the feasibility of depositing, by AP-CVD at intermediate temperatures, doped polycrystalline silicon films on glass substrates with interesting properties for photovoltaic applications. Moreover, the first trials of depositing heterojunction solar cells between p-type crystalline silicon and n-type polycrystalline silicon, gave encouraging results.