| 摘要 |
PURPOSE:To ensure the amplification effect even after micro-miniaturization by covering a base layer of the portion, where at least an emitter layer is not provided, with a protection film consisting of an insulator. CONSTITUTION:A mesa part is formed on an N-type GaSb substrate 1 on which a collector layer is formed and an N-type InAs layer 2 forming a base layer is formed on this mesa portion. An N-type GaSb layer 3 forming an emitter layer is then formed on this N-type InAs layer 2. These are all formed in the circular shape having planar surface. A ring type collector electrode 4 is formed on the circumference of the mesa part of the N-type GaSb substrate 1 through ohmic contact with the N-type GaSb substrate 1. Moreover, a circular base electrode 5 is formed on the N-type GaSb layer 3 through ohmic contact with the N-type GaSb layer 3. The portions not covered with the collector electrode 4 and emitter electrode 5 among the surfaces of the N-type GaSb substrate 1, N-type InAs layer 2 and N-type GaSb layer 3 are entirely covered with a resist film 6. |
