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Effects of boron doping on solid phase crystallization of in situ doped amorphous Silicon thin films prepared by electron beam evaporation

Sedani, Salar H.
Yasar, Ozlen F.
Karaman, Mehmet
Turan, Raşit
In this work, we studied solid-phase crystallization of boron-doped non-hydrogenated amorphous Si films fabricated by electron beam evaporation equipped with effusion cells (e-Beam EC) on silicon nitride coated glass substrates. We investigated the effect of boron doping on the crystallization kinetics through a series of experiments with different boron doping concentrations controlled by the effusion cell temperature. We employed Raman spectroscopy, time-of-flight secondary ion mass spectroscopy, grazing incidence X-ray diffraction, Hall Effect measurement and X-ray photoelectron spectroscopy (XPS) to understand the structural and electrical variations with regard to B doping and process conditions. We found that the stress in the poly-Si thin film increases when the B concentration increases from 10(18) to 10(20) atoms/cm(3), reaching a value of to 1087.5 MPa. We also studied the chemical environment around the B atoms by comparing the B-1s, binding energies in XPS measurements, which revealed that B-Si coordination does not change upon crystallization. The electrical effect of boron doping was observed in a drastic drop in resistivity from orders of 10(2) to the 10(-3) Omega.cm. Moreover, we found that an increase in boron doping concentration leads to a higher crystallization rate of non-hydrogenated amorphous silicon thin films prepared by e-Beam EC.