| 摘要 |
PROBLEM TO BE SOLVED: To improve the current amplification factor of a compound semiconductor device by suppressing the influence of lattice relaxation upon a contact layer. SOLUTION: In the compound semiconductor device in which a collector layer 3, a base layer 4, an emitter layer 5, and the InGaAlAs contact layer 6 are formed on a GaAs substrate 1 in this order, the contact layer 6 contains a first layer 6A which is in contact with an electrode metal in a state where the In composition of the layer 6 becomes the value required for obtaining a good ohmic contact state with the electrode metal and a second layer 6B which is provided in contact with the first layer 6A to reduce the influence of lattice relaxation. The second layer 6B is composed of a plurality of layers 61-65 and the In composition of the layer 6B has at least one layer interface the In composition of which changes along the thickness direction of the layer 6B. COPYRIGHT: (C)2004,JPO
|
