| 摘要 |
PROBLEM TO BE SOLVED: To provide a heterojunction bipolar transistor (HBT) capable of improving a high-frequency characteristic. SOLUTION: An energy level Ec in the vicinity of an interface beween a graded layer 1G and a ballast resistor 1R related to the embodiment is smoothly continued. This is why an increase in n-type impurity concentration C<SB>ION</SB>in the vicinity of the interface provides the presence of an ionized doner (having a positive charge) in the vicinity of the interface. That is, the ion of the doner cancels a spike-like potential barrier ϕ<SB>BARRIER</SB>protruding in a negative direction of the potential in the vicinity of the interface. Therefore, a resistance value of the HBT at room temperature is lowered to improve the high-frequency characteristic. COPYRIGHT: (C)2009,JPO&INPIT
|
