. . "after written as A-Si(H, X)), and alsocontains a p-type impurity such as B, etc. or a n-type impurity such as P, etc. as a substance for controlling electroconductivity.In the present invention, the content of the substance for controlling conductivity such as B, P, etc. contained in the intermediate layer 12 may be 10 preferably 0.001 to 5.times.10.sup.4 atomic ppm, more preferably 0.5 to 1.tim" . .