| 摘要 |
PURPOSE:To assure a large current driving capacity by forming a barrier layer constructing a quantum well as an AlGaAs layer where the composition of AlAs on the surface side is less than that on the side of a substrate beyond a specific value. CONSTITUTION:A double-hetero structure composed of layers 4-8 is formed after forming on a semi-insulating GaAs substrate 1 a non-doped Al0.3Ga0.7As layer 3 as a buffer layer. The layer 4 is an N type Al0.3Ga0.7As of a thickness of 50-150Angstrom , the layer 5 is a non-doped Al0.3Ga0.7As spacer layer of a thickness of about 20Angstrom , and the layer 6 is a InxGa1-xAs quantum well layer (x is less than 0.25) of a thickness of 100-200Angstrom . And, the layer 7 is a non-doped Al0.15 Ga0.35As spacer layer of a thickness of about 20Angstrom , and the layer 8 is an N type Al0.15Ga0.85As layer. An N type GaAs layer 9 is formed on the double hetero junction structure composed of the layers 4-8. The structure provides a higher two-dimentional electron gas concentration in the InxGa1-xAs quantum well layer 6. Thus maximum drive current is assured in a FET of a gate length of 1-0.5mum. |
