| 摘要 |
PURPOSE:To avoid degradation of the mobility and speed of carriers of a two-dimensional carrier gas layer in a carrier traveling semiconductor layer caused by LO (longitudinal optical) phonon scattering and improve sheet density by a method wherein one of two hetero-junction planes of which the two-dimensional carrier gas layer is composed is formed by laminating compound semiconductor layers which have no overlapping of oscillation frequency in the LO phonon branch. CONSTITUTION:1st and 2nd carrier supply layers 1 and 2, which supply carriers to a carrier traveling semiconductor layer 3 in which carriers exist locally and which are made of semiconductors with wider gaps compared to the gap of the carrier traveling semiconductor layer 3 as shown in an energy band model of a conduction band side, are provided on both sides of the layer 3 holding the layer 3 between them and 1st and 2nd hetero-junction planes J1 and J2 are formed. The two junction planes J1 and J2 are, or the one junction plane J1 is, composed of 1st and 2nd wide gap semiconductor thin film layers 11 and 12 which have wide band gaps. The thickness (a) of the carrier traveling semiconductor layer 3 in which carriers exist locally conforms to the relation a<=pi/q, wherein (q) is the momentum of the carrier, for instance electron, in the layer 3. |
