| 摘要 |
PURPOSE:To simply and effectively obtain a solar cell of high quality by so growing the GaAs of an upper layer as to cover a crack naturally generated by cooling in a GaAs thin film grown in a Si substrate shape. CONSTITUTION:An N-type Si substrate 10 is introduced into a MOSCVD unit, and a GaAs thin film is grown on the substrate 10. It is initially heated in H2 gas stream to remove an oxide film on the substrate 10. Thereafter, a GaAs film is formed by two-stage growing method. After an Se-doped layer is so grown as to become 5mum thick, the growth is interrupted, and a sample is cooled to room temperature. Thus, many cracks are introduced in the GaAs film due to the difference of thermal expansion coefficients of the Si of the substrate and the GaAs film. This is again heated to growing temperature, and an Se-doped AlGaAs which becomes the rear surface of a solar cell is grown approx. 0.5mum. An active layer N-N-GaAs, P-GaAs-P-AlGaAs (window layer)-P-GaAs (cap layer) are sequentially formed in this order in a solar cell on the AlGaAs. |
