| 摘要 |
PURPOSE: To nondestructively evaluate the crystallinity of crystals in the vicinity of a substrate without requiring a simple element, etc., by making a second compound semiconductor layer constitute a quantum layer along with a first and third compound semiconductor layers. CONSTITUTION: A buffer layer 16 is composed of a first AlGaAs layer 12 of a film thickness 200Å, a GaAs layer 13 of a film thickness 100Å, and a second AlGaAs layer 14 of a film thickness 3,000Å. In the case of a construction like this, a quantum well is formed in the GaAs layer 13, since the band gap energy of the AlGaAs layer differs from that of the GaAs layer, and the band gap energy of the GaAs layer is smaller than that of the AlGaAs layer. The luminescent strength by photoluminescence of this GaAs layer 13 is stronger compared to other layers, and its features are easy to detect. Accordingly, it becomes possible to evaluate whether or not the crystallinity of the GaAs layer 13 is satisfactory, by investigating the luminescent strength by photoluminescence measurement even with an active layer 15 kept laminated. |
