Effect of fluorine on metal-insulator-silicon solar cell performance with an low-temperature deposited SiO2 layer

Metal-insulator-silicon solar cells with an insulator layer fabricated by t he liquid phase deposition method, denoted as LPD-MIS solar cells, were stu died. Under the illumination, an output efficiency up to 7.2% was obtained. A photovoltaic phenomenon occurred even for an oxide thickness ranging fro m 50 to 150 Angstrom, which was much thicker than the limit of 30 Angstrom predicted by MIS theory. It was suggested that these interesting results ma y be due to barrier height enhancement and diode quality factor lowering ca used by a fluorine content incorporated in the SiO2 layer during the LPD-MI S solar cell fabrication process. The existence of fluorine content and its effect on LPD-MIS solar cell performances were investigated through AES, F TIR, and C-V characterizations. The hopping conduction mechanism was propos ed to explain the effect of the oxide traps, which were believed to be due to the fluorine incorporated in the LPD-SiO2 film. The results provided a g uideline for the fabrication of LPD-SiO2 related devices and showed that an extreme thin insulating layer in LPD-MIS solar cell was not a necessity. ( C) 1999 Elsevier Science S.A. All rights reserved.