| 摘要 |
PURPOSE:To enable operation at high speed by utilizing the difference of potential generated at a hetero interface between mutual semiconductors, electron affinity thereof differs. CONSTITUTION:An N type GaAs collector contact layer 2 is formed onto a semi-insulating GaAs substrate 1 not doped by utilizing a molecular beam epitaxial growth method. A collector layer 3 consisting of un-doped AlGaAs (an AlXGa1-XAs layer), a base layer 4 composed of a GaAs layer doped in an N type, an emitter layer 5 made up of an N type AlXGa1-XAs layer and an emitter contact layer 6 formed of an N type GaAs layer are shaped. An opening reaching a base is formed by plasma etching through mesa etching, and a GaAs layer 12 doped in an N type at high concentration is shaped. |
