| 摘要 |
PURPOSE:To form a base layer having an inclination type energy band gap, with superior controllability and reproducibility, by performing a vapor phase epitaxy changing the radiation amount of light. CONSTITUTION:On an n-type GaAs substrate 1, a collector layer 2 of an n-type GaAs layer is grown, and thereon, a p-type AlxGa1-xAs (x<=0.2) base layer 3 is grown while the radiation amount of KrF eximer laser light 4 is gradually increased. In this process, the Al composition (x) of the growth layer increases up to 0.2 in proportion to the increase of radiation amount of the laser light 4. The energy band gap gradually varies with the change of the composition. By forming the base layer 3 in the manner in which a vapor growth or especially an organic metal vapor growth is applied, while the radiation amount of light projected on the epitaxial growth surface is changed, the base layer whose composition gradually changes can be formed with excellent controllabily and reproduciablity.
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