Semiconductor device and method of fabricating the same

A semiconductor device fabricating method comprising:

• the step (a), of forming a gate electrode on a semiconductor substrate of first conductive type with a gate insulating film interposed therebetween;
• the step (b), of forming side walls made of an insulating film at the lateral sides of said gate electrode on said semiconductor substrate;
• the step (c), of forming first semiconductor layers made of single-crystal silicon films relatively superior in crystallinity for epitaxial growth respectively on a surface of said semiconductor substrate at both lateral sides of said gate electrode with said side walls interposed therebetween by treating epitaxial growth at a lower growth rate;
• the step (d), of forming second semiconductor layers made of single-crystal films or polycrystalline films, which are relatively inferior in crystallinity for epitaxial growth, or amorphous films respectively on said first semiconductor layers by treating epitaxial growth at a higher growth rate;
• and
• the step (e), of forming first impurity layers of second conductive type, respectively serving as a source and a drain in a region extending from the upper areas of said first semiconductor layers to the whole areas of said second semiconductor layers.