| 摘要 |
PROBLEM TO BE SOLVED: To reduce resistance of an n-type InGaAs non-alloy layer. SOLUTION: On a semi-insulating GaAs substrate 1, an n-type sub-collector layer 2, an n-type collector layer 3, a p-type base layer 4, an n-type emitter layer 5, and an n-type InGaAs non-alloy layer 10 are formed in order. The n-type InGaAs non-alloy layer 10 is composed of an n-type InGaAs graded layer 10a in which an In composition is inhomogenous (inhomogenous composition layer) and an n-type InGaAs homogenous layer 9 in which the In composition is homogenous, on the graded layer 10a. The graded layer 10a is composed of a first graded layer 7 (first layer) in which In composition is low, and a second graded layer 8 (second layer) in which the In composition is higher than that in the first graded layer 7. In the first graded layer 7, the background concentration of C (carbon) in the In composition is suppressed, and Si is doped for obtaining carrier concentration higher than that in the case of doping Se as an n-type dopant. COPYRIGHT: (C)2007,JPO&INPIT
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