| 摘要 |
PURPOSE: To provide a semiconductor functional element which has a single-peak current-voltage characteristic and can sufficiently suppress the increase of an electric current when an applied voltage is higher than the valley voltage by providing a barrier layer of an undoped semiconductor to which no impurity element is added between a semi-insulating semiconductor substrate and a collector layer. CONSTITUTION: When an undoped InAlAs layer 2 is interposed between a semi- insulating semiconductor substrate 1 and an n-type InGaAs layer 3, the pinch-off effect of the substrate 1 on the electrons flowing in the layer 3 in the lateral direction can be intensified, because a barrier which prevents the leakage of electrons to the substrate 1 side is provided and the barrier surely encloses electrons within the layer 3. In other words, the increase of electric current can be sufficiently controlled when a voltage higher than the pinching-off voltage is applied and a current-voltage characteristic having a single-peak current characteristic can be realized easily. |
