Semiconductor device especially MOSFET or flash EEPROM

摘要

A semiconductor device has a first conductivity type semiconductor substrate (1) with a main surface containing a pair of spaced-apart impurity regions (2a, 2b, 3a, 3b) of opposite second conductivity type, a channel region formed between the impurity regions and enclosed by an insulating film (4a), and an electrode (5) formed on the insulating film. The novelty is that (a) the insulating film (4a) has uniform thickness and has nitrogen-containing end regions (4d) in contact with the pair of impurity regions; or (b) the insulating film has nitrogen-containing end regions in contact with the pair of impurity regions and, between these nitrogen-containing end regions, a region which has lower nitrogen impurity concentration and greater thickness than the end regions. Also claimed are processes for producing a semiconductor device.