| 摘要 |
PURPOSE:To form a highly pure, high quality epitaxial layer in a compound semiconductor such as HEMT and to improve characteristics of a semiconductor device, by forming a buffer layer having a super-lattice structure of (AlAs)m and (GaAs)n on a GaAs substrate, and epitaxially growing the compound semiconductor thereon. CONSTITUTION:A semiconductor lyaer 5, which is to become an operating region, is epitaxially grown on a GaAs substrate 1 through a buffer layer 2 having a super-lattice structure of (AlAs)m and (GaAs)n, where m>=6 and cycles are one or more periods. For example, on a semi-insulating GaAs substrate 1, in which Cr is doped, a super-lattice buffer layer 2 characterized by (AlAs)6(GaAS)6 and 2-3 periods is formed. A first semiconductor layer 13 comprising a GaAs layer, in which impurities are not doped, is formed thereon. A second semiconductor layer 14 comprising a non-doped AlGa layer is formed on the layer 13. A third semiconductor layer 15 comprising N-type Al0.3Ga0.7As layer is formed on the layer 14. A Schottky gate electrode 16 is deposited on the layer 15. A source electrode 17 and a drain electrode 18 are ohmic-contacted on both sides of the electrode 16. Thus an HEMT is formed. |
