A method is disclosed for integrally forming at least one low voltage
device and at least one high voltage device. According to the method, a
first gate structure and a second gate structure are formed on a
semiconductor substrate, wherein the first and second gate structures are
isolated from one another. One or more first double diffused regions are
formed adjacent to the first gate structure in the semiconductor
substrate. One or more second double diffused regions are formed adjacent
to the second gate structure in the semiconductor substrate. One or more
first source/drain regions are formed within the first double diffused
regions. One or more second source/drain regions are formed within the
second double diffused regions. The first double diffused regions
function as one or more lightly doped source/drain regions for the low
voltage device.