| 摘要 |
PURPOSE:To reduce a cost and a weight and improve performance by a method wherein the first Ge layer of moderate quality is formed on an Si substrate and a Ge layer of high quality is formed on the first Ge layer and further a III-V group compound semiconductor layer is formed on the second Ge layer. CONSTITUTION:The first Ge layer 10 is made to grow on an Si substrate 9 by a molecular beam epitaxial apparatus. The preferable thickness of the first Ge layer 10 is 0.5mum-2.0mum. By thermal decomposition of germane, the second Ge layer 11 is made to grow on the first Ge layer 10 by epitaxial growth to form the high quality second Ge layer 11 with a thickness of about 2-5mum. Then, on the second Ge layer 11, an N-type GaAs layer 2 with a thickness of 2.5mum, a P-type GaAs layer 3 with a thickness of 0.5mum, a P-N junction 4 and a P-type AlGaAs layer 5 with a thickness of 0.05mum are formed by a method such as organic metal vapor phase deposition. A reflection preventing film 6, a P-type electrode 7 and an N-type electrode 12 can be formed by the same method as applied to a conventional Si solar battery or the like. With this constitution, the weight efficiency can be made larger than that of a conventional GaAs solar battery with a thickness of 300mum. |
