| 摘要 |
PURPOSE:To prevent the travelling speed of electrons from reducing due to gamma-L trough scattering in a collector barrier by a method wherein the composition ratio of Al in an InAlGaAs-made collector barrier is designed to decrease from the base layer side toward the collector layer side for the InAlGaAs to be finally InGaAs. CONSTITUTION:On an InP substrate 1, an n<+>In0.53Ga0.47As collector layer is formed by MBE or the like. Next, an In0.52(AlxGa1-x)0.48As (the Al composition ratio being so graded as to satisfy x=0 0.5) collector barrier layer 3A, an n-In0.53Ga0.47As base layer 4, an In0.53Al0.47As barrier layer 5, an In0.53Ga0.47As well layer 6, a quantum well layer that is an In0.53Al0.47As barrier layer 7, and an n<+>In0.53Ga0.47As emitter layer 8 are grown. The Al in the collector barrier layer 3A, the component contributing to the reduction of DELTAE(gamma-L) in the InAlGaAs, is so designed as to gradually decrease from the base side toward the collector side, which gradually increases DELTAE, for the prevention of scattering in the gamma-L trough. |
