| 摘要 |
PURPOSE:To select resonance hot electron transistors (PHET) and hot electron transistors (HET) optionally and reduce the number of devices significantly and reduce a delay time by a method wherein an RHET device is formed on the barrier side of a semiconductor substrate to which a quantum well structure is provided and an HET device is formed on the barrier side to which no quantum well structure is provided. CONSTITUTION:At least four layers of N-type semiconductor layers N1-N4 are laminated with nondoped barriers B1-B3 between and the one barrier at the uppermost layer or the lowermost layer, for instance the barrier B3 has a quantum well structure in which a well layer B3W is sandwiched between barrier layers B31 and B32. An RHET device is composed of the N-type semiconductor layer N3, which is sandwiched between the barrier B3 with the quantum well structure and the center barrier B2, as a base layer B and the N-type semiconductor layer N4 as an emitter. An HET device is formed by using the N-type semiconductor layer N2 provided between the barriers B1 and B2 which have no quantum well as a base layer B. If the N-type semiconductor layer N3 is used as a collector layer C of the HET device, the barriers between the bases and the collectors of the two devices can be gathered into the barrier B3 and the barrier B1 can be optimized as the barrier between the emitter and the base of the HET device. |
