Microstructural and electrical properties of different-sized aluminum-alloyed contacts and their layer system on silicon surfaces

摘要: Abstract The firing of screen-printed aluminum pastes is well established for the formation a back surface field (BSF) and contacts since many years in silicon solar cell fabrication. In this paper we investigate electrical microstructural properties Al-alloyed their layer system, consisting (i) Al-doped p+-layer (2–14 μm), eutectic (1–15 μm) paste residuals (20–100 μm). We show influence process parameters like amount printed paste, alloying time peak temperature. Special emphasis devoted to small alloyed structures local contacts. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), electrochemical capacitance voltage (ECV) conductivity measurements have been applied characterize samples. A simple model qualitatively augmented describe all effects occurring technical process. For example, increasing amounts, saturation thickness was found range 10 mg/cm2. structures, formed very homogenously with greater compared samples full-area Al metallization, which processed similar conditions. high about 16×106 S/m, only 2–3 times below that pure has determined. This advantageous lateral especially amounts feature relatively thick layer.