| 摘要 |
In a semiconductor film having a heterojunction structure, for example a semiconductor film ( 11 ) including a SiGe layer ( 2 ) and a Si layer ( 3 ) formed on the SiGe layer ( 2 ), impurity concentration is controlled in such a manner that the concentration of impurity in the lower, SiGe layer ( 2 ) becomes higher than that in the upper, Si layer ( 3 ) by exploiting the fact that there is a difference between the SiGe layer ( 2 ) and the Si layer ( 3 ) in the diffusion coefficient of the impurity. The impurity contained in the semiconductor film 11 is of the conductivity type opposite to that of the transistor (p-type in the case of an n-type MOS transistor whereas n-type in the case of a p-type MOS transistor). In this way, the mobility in a semiconductor device including a semiconductor film having a heterojunction structure with a compression strain structure is increased, thereby improving the transistor characteristics and reliability of the device.
|
