Semiconductor device and method of fabricating the same

A semiconductor device comprising:

• a semiconductor substrate;
• a gate insulating film and a gate electrode formed on said semiconductor substrate;
• a pair of sidewall insulating films formed on the lateral portions of said gate electrode;
• a pair of first P-type impurity-diffused layers formed in the surficial portion of said semiconductor substrate at a first depth so as to be self-aligned with respect to said gate electrode;
• a pair of second P-type impurity-diffused layers formed in the surficial portion of said semiconductor substrate at a second depth deeper than said first depth so as to be self-aligned with respect to said gate electrode and said sidewall insulating films;
• and
• a pair of N-type impurity-diffused layers containing phosphorus formed between said pair of second P-type impurity-diffused layers, and respectively in adjacent to each of said pair of first P-type impurity-diffused layers.

A method of fabricating a semiconductor device comprising the steps of:

• forming a gate insulating film and a gate electrode on a semiconductor substrate;
• forming a pair of P-type impurity-diffused layers by introducing a P-type impurity into the surficial portion of said semiconductor substrate with using said gate electrode as a mask;
• forming a pair of first sidewall insulating films on the lateral portions of said gate electrode;
• forming a pair of first N-type impurity-diffused layers at a first depth by introducing at least phosphorus into the surficial portion of said semiconductor substrate with using said gate electrode and said first sidewall insulating films as a mask;
• forming a pair of second sidewall insulating films so as to sandwich the said first sidewall insulating films with said gate electrode, and so as to have a width larger than that of said first sidewall insulating films;
• and
• forming a pair of second N-type impurity-diffused layers at a second depth deeper than said first depth by introducing an N-type impurity into the surficial portion of said semiconductor substrate with using said gate electrode, said first sidewall insulating films and said second sidewall insulating films as a mask.

A method of fabricating a semiconductor device comprising the steps of:

• forming a gate insulating film and a gate electrode on a semiconductor substrate;
• forming a pair of N-type impurity-diffused layers by introducing at least phosphorus into the surficial portion of said semiconductor substrate with using said gate electrode as a mask;
• forming a pair of first P-type impurity-diffused layers at a first depth by introducing a P-type impurity into the surficial portion of said semiconductor substrate with using said gate electrode as a mask;
• forming a pair of sidewall insulating films on the lateral portions of said gate electrode;
• and
• forming a pair of second P-type impurity-diffused layers at a second depth deeper than said first depth by introducing a P-type impurity into the surficial portion of said semiconductor substrate with using said gate electrode and said sidewall insulating films as a mask.