| 摘要 |
PURPOSE:To obtain a photodetector with a high speed optical response characteristic and a sensible wavelength range extending to the side of a long wavelength by making a superlattice layer a light absorbing layer and, at the same time, forming a two-dimensional electron gas region on an interface between the superlattice layer and a spacer layer. CONSTITUTION:An undoped GaAs (p-type) buffer layer 2 and a distorted superlattice layer 3 wherein an undoped InAs well layer 31 and an undoped GaAs barrier layer 32 are laminated by two periods or more are provided on a semiinsulative p-type GaSb (100) substrate (p-type semiconductor substrate) 1. An undoped Al0.4Ga0.6As spacer layer 4, an n-type Al0.4Ga0.6As electric charge supply layer 5 and an n-type GaAs contact layer 6 are sequentially laminated, the contact layer 6 is removed except a light incident portion and Au-Ge is attached thereto and alloyed to form drain and source electrodes 7 and 8, respectively. Thus, since incident light is absorbed by the distorted superlattice layer 3 and a two-dimensional electron gas region 10 is produced in the distorted superlattice layer 3 having little alloy scattering, the mobility of electrons is large and therefore a photodetector respond to light at high speed.
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