Thin film Semiconductor device and method of manufacturing the same

摘要

Problems in prior art regarding an n-channel TFT in the source / drain gettering method are solved. In the n-channel TFT, its source / drain regions contain only an n-type impurity. Therefore, compared to a p-channel TFT whose source / drain regions contain an n-type impurity and a higher concentration of p-type impurity, the gettering efficiency is inferior in a channel region of the n-channel transistor. Accordingly, the problem of inferior gettering efficiency in the n-channel TFT can be solved by providing at an end of its source / drain regions a highly efficient gettering region that contains an n-type impurity and a p-type impurity both with the concentration of the p-type impurity set higher than the concentration of the n-type impurity.