Method for making semiconductor device with metal deposited on electron donating surface of gate electrode

Claim 1

In a method for fabricating a semiconductor device comprising: (i) a semiconductor substrate; (ii) source and drain regions formed within said semiconductor substrate; (iii) a gate insulating film provided on said semiconductor substrate, (iv) a first gate electrode provided on said gate insulating film; and (v) a second gate electrode covering an upper surface and both side surfaces of said first gate electrode, the improvement which comprises: (a) forming said first gate electrode; (b) implanting an impurity using said first gate electrode as a mask to form first regions in said semiconductor substrate for forming said source and drain regions; (c) forming said second gate electrode by selective chemical vapor deposition employing hydrogen gas and at least one gas selected from the group consisting of TiCl 4 , Cu(C 11 H 19 O 2 ) 2 , Cu(C 5 H 7 O 2 ) 2 , W(CH 3 ) 3 , W(C 2 H 5 ) 3 , Mo(CO) 6 and alkylaluminum hydride; and (d) implanting an impurity using said second gate electrode as a mask to form second regions in which impurity concentrations are higher than in said first regions in said semiconductor substrate, wherein there is a self-alignment between edge portions of said first and second regions with the first and second gate electrodes.