Growth and doping of Si layers by molecular-jet chemical vapor deposition: Device fabrication

Homoepitaxial Si films doped both n- and p-type were deposited by molecular-jet chemical vapor deposition (CVD) from 10% Si₂H₆ in H₂. Doping was accomplished from the background using PH₃ for n-type and B₂H₆ for p-type. The dopant concentration was controlled over four orders of magnitude (10¹⁵-10¹⁹ cm^-2) for films deposited between 650 and 800°C, and n-type films had significantly higher growth rates and doping levels compared to films deposited by very-low pressure CVD at equal Si₂H₆ throughput in the same reactor. Even without optimization, solar cells constructed from these films had open-circuit voltages and short-circuit currents as high as 490 mV and 21 mA cm^-2, respectively, with fill factors as high as 70%.