| 摘要 |
According to one embodiment of the invention, a method of forming an asymmetric I/O transistor includes forming a first oxide layer outwardly from a semiconductor substrate, masking a first portion, less than a whole portion, of an I/O transistor region with a first photoresist layer, removing the first oxide layer from a core transistor region and a second portion of the I/O transistor region, removing the first photoresist layer, forming a second oxide layer outwardly from the substrate, forming gates for the core transistor region and the I/O transistor region, masking the first portion of the I/O transistor region with a second photoresist layer, doping a source region and a drain region of the core transistor region and a source region of the I/O transistor region with a first dopant, doping the source region and the drain region of the core transistor region and the source region of the I/O transistor region with a second dopant, removing the second photoresist layer, masking the core transistor region and the second portion of the I/O transistor region with a third photoresist layer, and doping a drain region of the I/O transistor region with a third dopant.
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