| 摘要 |
PURPOSE:To enhance two-dimensional gas concentration and to make current driving capability large, by providing a low-impurity-concentration, n-type AlGaAs layer in the vicinity of a heterojunction interface, and providing a high-impurity-concentration, n-type AlGaAs layer at a position separated from the vicinity of the heterojunction interface. CONSTITUTION:A non-doped semiconductor channel layer 2 is formed on a semi-insulating crystal substrate 1. A semiconductor electron supplying layer 4 is formed on the channel layer 2. At this time, the supplying layer 4 is formed by a low-impurity-concentration, n-type AlGaAs layer 4A in the vicinity of a heterojunction interface and a high-impurity-concentration, n-type AlGaAs layer 4B at a position separated from the vicinity of the heterojunction interface. The optimum thickness of the layer 4A is about 10-20 [Angstrom ]. Thus, two-dimensional electron gas concentration is enhanced, and current driving capability becomes large. |
