Method of manufacturing a LDD-MOSFET

摘要

For the production of a semiconductor device, a gate oxide film (12) is formed on a silicon substrate (11). Polysilicon is deposited on the gate oxide film (12) and then subjected to photolithography. The polysilicon is patterned to form a gate electrode (13). Subsequently, a silicon oxide film or similar thin film (14) is formed on the entire surface of the laminate. The depth of an amorphous layer (15) to be formed by ion implantation later is calculated beforehand on the basis of the dose of ion implantation. The thin film (14) has its thickness selected to be four times or more greater than the calculated depth. Subsequently, arsenic ions (As<+>) are implanted in the substrate (11) via the thin film (14), thereby forming the amorphous layer (15) in the surface of the substrate (11). The resulting laminate is annealed in order to activate the impurity and recrystallize the amorphous layer (15). Because the Ä111Ü plane does not appear, only epitaxial grow in the direction perpendicular to the Ä100Ü direction occurs. Therefore, a diffusion layer (16) free from a crystal lattice defect at its edge is achieved.